| Extension | File Type | Files scanned | Contributor |
| C10 | Virtual MC-10 tape image | 13 | |
| C3 | 3D model | 3 | |
| C3D | Chem3D Format | 21 | |
| C3D | Coordinate 3D (subset of ADTech File Format) file (common) | 36 | |
| C3D | Coordinate 3D (subset of ADTech File Format) file (more generic) | 37 | |
| C3XML | Chem3D XML format | 6 | |
| C4* | Clonk game data | 20 | |
| C4D | CINEMA 4D model (generic) | 14 | |
| C64 | PC64/DOS Saved Session image/dump | 2 | |
| CAB | InstallShield compressed Archive | 14 | |
| CAB | Microsoft Cabinet Archive | 17 | |
| CAD | CadStd drawing | 8 | |
| CAD | Drafix Windows CAD drawing | 4 | |
| CAD | EXTRACAD drawing | 4 | |
| CAD | GenCAD layout | 11 | |
| CAD | QuickCAD Drawing | 6 | |
| CAF | Cal3D Animation File | 3 | |
| CAF | Cathy catalog | 659 | aNDreas Bolota |
| CAF | Core Audio File | 9 | |
| CAG | Capella gallery data file | 7 | Joachim Grabinski |
| CAI | SeeYou flight data | 9 | |
| CAJ | CAJ database | 13 | |
| CAK/CPK/SND/FILM | Sega FILM/CPK video | 5 | |
| CAL | QV Map Calibration data | 16 | |
| CAL | SuperCalc worksheet | 5 | |
| CAL | Windows Calendar | 7 | |
| CAL/CALS | CALS raster bitmap | 6 | |
| CAM | Casio QV digital CAMera bitmap | 2 | |
| CAMPROJ | Camtasia Studio Project | 11 | |
| CAMPROJ | Camtasia Studio Project (UTF) | 15 | |
| CAMREC | Camtasia Studio Screen Recording | 10 | |
| CAP | Capella sheet data file | 232 | Joachim Grabinski |
| CAP | Generic network capture file (XCP style) | 4 | |
| CAP | Microsoft NetMon v1.x traffic capture | 5 | |
| CAP | Microsoft NetMon v2.x traffic capture | 8 | |
| CAP | Snoop capture file | 3 | |
| CAR | Biosym archive | 6 | |
| CAR | CAR compressed archive | 4 | |
| CAR | Carnivores /2 /Ice Age animal and object graphics and behavior file | 27 | Dinoguy1000 |
| CAR | Carrara Environment | 12 | |
| CAR | Cellsprings CA Rule | 6 | |
| CAR | NASCAR Racing Car description | 30 | |
| CAR | SAPCAR CAR archive | 2 | |
| CAS | Fluent case | 6 | |
| CAS | MSX cassette tape image | 19 | |
| CAT | Microsoft Security Catalog | 31 | |
| CATDRAWING | CATIA Drawing (generic) | 74 | |
| CATDRAWING | CATIA Drawing (v5 r10) | 8 | |
| CATDRAWING | CATIA Drawing (v5 r11) | 8 | |
| CATDRAWING | CATIA Drawing (v5 r14) | 8 | |
| CATDRAWING | CATIA Drawing (v5 r15) | 8 | |
| CATDRAWING | CATIA Drawing (v5 r16) | 8 | |
| CATDRAWING | CATIA Drawing (v5 r17) | 24 | |
| CATDRAWING | CATIA Drawing (v5 r18) | 16 | |
| CATDRAWING | CATIA Drawing (v5 r19) | 8 | |
| CATPART | CATIA Part Description | 24 | |
| CATPRODUCT | CATIA V5 data (generic) | 38 | |
| CAZ | CAZIP compressed file | 3 | |
| CAZ | CAZIPXP compressed archive | 3 | |
| CBCX | Comic Book Creator document | 5 | |
| CBCX | Comic Book Creator document (Unicode) | 7 | |
| CBD | MapBrowser - MapWriter vector map data | 2 | |
| CBDS | Comic Book DS | 4 | |
| CBF | CoffeeCup Button Factory button | 14 | |
| CBF | RKS Software Clandar Builder saved calendar | 7 | |
| CBIN | CACTVS (binary format) | 2 | |
| CBP | Code::Blocks Project | 7 | |
| CBS | Codebreaker save | 11 | |
| CBS | RKS Software Clandar Builder Style Sheet | 9 | |
| CBV | ChessBase Archive file | 11 | |
| CC | Kodak Color Control profile | 45 | |
| CCA | Multimedia Fusion - Click'n'Create file | 30 | |
| CCD | Elaborate Bytes/SlySoft CloneCD CDImage (description) | 14 | THE LoW |
| CCF | Component Configuration File (generic) | 7 | |
| CCF | Wii Virtual Console CCF archive | 3 | |
| CCRF | Saba Centra Recording Studio recording | 4 | Chris Clemson |
| CCS | CableNut Custom Settings | 7 | |
| CCT | Macromedia Director Shockwave Cast | 16 | |
| CD | Class Diagram (Unicode) | 4 | |
| CDA | CD Audio track shortcut | 15 | |
| CDB | Mactive AdBase data | 2 | |
| CDB | Pocket Access database | 14 | |
| CDB | Sangduck database | 2 | |
| CDD | Cadifra Diagram | 4 | |
| CDD | Claris Draw document | 18 | |
| CDD | ConceptDraw document | 4 | |
| CDDS | Midtown Madness 3 data | 5 | |
| CDF | Affymetrix Chip Definition File (Text) | 7 | |
| CDF | Channel Definition Format | 3 | |
| CDF | Computable Document Format | 12 | |
| CDL | CD Label Pro project | 2 | |
| CDL | NetCDF (network Common Data Form) | 14 | |
| CDM | NTI CD Maker image file | 4 | |
| CDM | PowerDesigner Conceptual Model | 13 | |
| CDPZ | ConceptDraw Project document (Zipped) | 30 | |
| CDR | CorelDRAW drawing (zipped) | 13 | |
| CDR | CorelDraw Document | 66 | |
| CDR | Elite Plus Commander file / saved game | 5 | |
| CDRZIP | DICOM Images zipped archive | 6 | |
| CDW | CeledyDraw drawing | 54 | |
| CDW | KOMPAS Drawing | 10 | |
| CDX | ChemDraw model | 17 | |
| CDX | Compound index MS Visual FoxPro 7 | 180 | Nicola Marangon |
| CDX | Sybase iAnywhere index files | 207 | Knuth Konrad |
| CDXML | ChemDraw XML | 11 | |
| CDZ | pSX compressed CD image | 10 | |
| CE1 | ComputerEyes Raw Data Format low-res bitmap | 5 | |
| CE2 | ComputerEyes Raw Data Format hi-res bitmap | 5 | |
| CEB | Apabi eBook | 10 | |
| CEF | Cereal Encrypted File | 2 | |
| CEG | Continuous Edge Graphic bitmap | 7 | |
| CEL | Affymetrix Probe Results (Bin) | 4 | |
| CEL | Affymetrix Probe Results (Text) | 4 | |
| CEL | Autodesk FLIC Image File (extensions: flc, fli, cel) | 59 | Alex Paven |
| CEL | Celestia script | 9 | |
| CEL | Lumena CEL bitmap | 15 | |
| CER | Internet Security Certificate | 11 | |
| CER/MSI | MSI/Accelrys Cerius II | 4 | |
| CFDG | Context Free design grammar | 46 | |
| CFG | Linksys NVRAM configuration dump | 2 | |
| CFG | MS Flight Simulator aircraft configuration file | 18 | |
| CFG | ShowMiiWads configuration | 4 | |
| CFL | Compressed File Library 3 compressed data | 3 | |
| CFM | ColdFusion Template | 2 | |
| CFML | ColdFusion Markup Language | 3 | |
| CFN | Calamus Font Data | 2 | |
| CFT | ChiWriter low resolution screen font. | 17 | |
| CGF | EGrid32 Compilable Grid Format (ready to be compiled) | 2 | Elias Montoya |
| CGF | EGrid32 Compilable Grid Format (ready to be modified) | 2 | Elias Montoya |
| CGM | Computer Graphics Metafile | 464 | |
| CGM | Computer Graphics Metafile (Clear Text) | 12 | |
| CGP | DVDFab Change Graphic Picture | 4 | |
| CGP | NetCaptor's CaptorGroup | 5 | |
| CGR | Quest3D data | 14 | |
| CGT | GOLD Parser Tables | 7 | |
| CH | Ch file format | 2 | |
| CH | Ch file format (encrypted) | 4 | |
| CH3 | Harvard Graphics Chart(v3.0) | 4 | |
| CHD | MAME Compressed Hard Disk image | 2 | |
| CHESSTITANSSAVE-MS | Microsoft Chess Titans Saved game | 5 | |
| CHI | ChiWriter document (v3.x or older) | 4 | |
| CHI | ChiWriter document (v4.x) | 8 | |
| CHI | Chip Tracker module | 2 | |
| CHI | Windows HELP Index | 213 | |
| CHK | PolySpace check results | 7923 | aNDreas Bolota |
| CHL | Black and White 2 game data script | 6 | |
| CHL | Chile compressed file | 2 | |
| CHM | Windows HELP File | 226 | Davide "Airex" Airaghi |
| CHN | ApBasic Chain file/module | 3 | |
| CHP | CHP! - CH compressor for Picture! compressed bitmap | 2 | |
| CHP | Ventura Publisher Chapter | 52 | |
| CHR | BGI (Borland Graphics Interface) font | 18 | |
| CHR | Infinity Engine exported player character (v1.0) | 5 | |
| CHT/SCT | SPSS template | 6 | |
| CHU | Infinity Engine user interface description (V1) | 2 | |
| CHZ | ChArc compressed archive | 5 | |
| CIF | Crystallographic Information File | 16 | |
| CIL | Clip Gallery Download Package | 3 | |
| CIN | Calculux Indoor project | 2 | |
| CIN | Cinemaware CIN Music | 11 | |
| CIN | Id Software Quake II Cinematic video | 4 | |
| CIN | Kodak Cineon bitmap | 23 | |
| CINEMA4D | Cinema 4D project | 7 | |
| CIRCUIT | KTechlab circuit design | 7 | |
| CIV5SAVE | Civilization V saved game | 15 | |
| CKD | Cadkey Design file | 6 | |
| CKD | KeyCreator Design file | 5 | |
| CKT | CircuitMaker schematic | 92 | Renan |
| CL4 | Easy CD Creator 4 Layout | 14 | |
| CL5 | Easy CD Creator 5 Layout | 14 | |
| CLA | CLASS336 Markup Language | 6 | |
| CLASS | Java Bytecode | 180 | |
| CLB | COM+ catalog file | 7 | |
| CLBX | MP3 Automagic CD Cover Creator label | 6 | |
| CLF | ListPro data | 14 | |
| CLG | Collage Maker document | 4 | |
| CLK | ClickFORMS data | 8 | |
| CLK | Corel R.A.V.E. Animation | 9 | |
| CLK | WatchGuard cloaked file | 2 | |
| CLKX | Crick Software Clicker File | 18 | Andrew Burt |
| CLMOV | Clan Lord movie - Visiostone | 8 | |
| CLO | SPSS Chart Look | 8 | |
| CLP | DeskMate clipart | 28 | |
| CLPI | Blu-ray Clip AV stream | 4 | |
| CLR | Macromedia Flash Color Table File | 8 | .Cryorb |
| CLS | Visual Basic class definition | 24 | |
| CMB | Reason Combinator Instrument Patch | 8 | |
| CMBL | Vernier Logger Pro data | 64 | |
| CMD5 | CrystalMaker Data format (v5-6) | 1802 | |
| CMD5/CMDF/CMMF | CrystalMaker Data format (generic) | 1860 | |
| CMDF | CrystalMaker Data format (v2-4) | 22 | |
| CMF | Cal3D Mesh File | 2 | |
| CMF | Creative Music File | 2 | |
| CMF | Sangduck Map | 2 | |
| CMG | Chessmaster saved game (10th ed.) | 2 | |
| CMG | Chessmaster saved game (generic) | 2 | |
| CMG | Cramfs ROM filesystem package | 3 | |
| CML | Chemical Markup Language | 34 | |
| CML | Chemical Markup Language XML document | 5 | |
| CMOD | Celestia 3D model (ASCII) | 2 | |
| CMOD | Celestia 3D model (binary) | 3 | |
| CMP | AUKTOOLS 2000 compressed archive | 3 | David J Walker |
| CMP | THEOS compressed archive | 11 | |
| CMPROJ | Channel Master Project | 36 | |
| CMU | CMU Window Manager bitmap | 19 | |
| CMU | CMU format - Andrew Toolkit | 3 | |
| CMV | Corel Movie animation | 3 | |
| CMX | Corel Metafile Exchange Image | 52 | Alex Paven |
| CNC3REPLAY | Command and Conquer 3 replay | 4 | |
| CNDF | Compressed Channel Data File | 4 | |
| CNF | PlayStation 2 system configuration | 3 | |
| CNT | Help File Contents | 5 | |
| CNV | DB2 Conversion File | 52 | Roberto 'rbnet' Bolli |
| CO | Cult3D object | 9 | |
| COB | Caligari TrueSpace Object | 23 | |
| COD | Blackberry Binary Executable | 20 | |
| COD | Forte Agent Charmap | 38 | fenixproductions |
| COL | Grand Theft Auto 3 collision data | 5 | |
| COL | HTML Help Collection | 6 | |
| COL | IFF Color Map - Palette | 10 | |
| COM | 16bit DOS command MoonRock+Arrowsoft Asm. | 16 | |
| COM | ASIC compiled DOS COM | 8 | |
| COM | Borland Turbo Pascal 3.0x DOS Command | 8 | |
| COM | EICAR antivirus test file | 2 | |
| COM | ICE compressed/scrambled DOS Command | 3 | |
| COM | LGLZ compressed DOS command | 16 | |
| COM | Shrink packed DOS Command | 14 | |
| COM | Six-2-Four (624) packed DOS Command | 13 | |
| COMFYCAKESSAVE-MS | Comfy Cakes saved game | 6 | |
| COMPANYLOGO | CompanyLogoDesigner project file | 429 | Thomas Holz |
| CONF | fswebcam configuration | 4 | |
| CONF | psitree router configuration | 11 | |
| CONTACT | Windows Contact | 20 | |
| CONTROL | HEC-HMS Control specifications data | 3 | |
| CPC/CPI | Cartesian Perceptual Compression image | 13 | |
| CPCK | Professor Layton game data package | 2 | |
| CPE | Windows FAX cover | 4 | |
| CPG | Cool Page Project | 24 | |
| CPH | Corel PrintHouse image | 10 | |
| CPI | AVCHD Clip Information | 6 | |
| CPI | International Code Page file | 16 | |
| CPI | Sietronics CPI XRD format | 9 | |
| CPIO | CPIO ASCII archive | 2 | |
| CPJ | WinOnCD Project | 8 | |
| CPL | Corel Color Palette | 100 | |
| CPL | Win 9x/ME Control Panel applet | 105 | |
| CPR | CPC Plus Cartridge image | 18 | |
| CPR | Cubase Project | 26 | |
| CPS | Corel PhotoHouse image | 12 | |
| CPT | Corel Photo Paint | 384 | |
| CPT | DTS Compact audio | 3 | |
| CPT | Mac Compactor (Pro) Archive | 8 | |
| CPV | Polytron VCS logfile | 2 | |
| CPX | Windows codepage translator | 7 | |
| CR2 | RAW File from Canon digital camera | 9 | |
| CRB | Enter a useful file type description | 3 | |
| CRC | Total Commander CRC file | 2 | |
| CRD | Microsoft Windows 3.x Cardfile database | 2 | |
| CRE | Infinity Engine creature (v1.0) | 2 | |
| CRE | Infinity Engine creature (v1.2) | 2 | |
| CRF | Cal3D material File | 2 | |
| CRF/CCRF/PRN | Calcomp raster bitmap | 90 | |
| CRS | StepMania Course | 4 | |
| CRT | C64 Cartridge image | 18 | TLG |
| CRT | Security Certificate | 6 | |
| CRT | X.509v3 security certificate | 17 | |
| CRU | Crush compressed archive | 7 | |
| CRV | Corel PhotoPaint Tone Curve | 10 | |
| CRW | RAW File from Canon digital camera | 153 | Roberto 'rbnet' Bolli |
| CRX | Google Chrome Extension | 8 | |
| CRYPT | Cryptx encrypted data | 2 | |
| CRYPTOMITE | CryptoMite encrypted | 21 | |
| CRYPTOMITE | CryptoMite encrypted archive | 5 | |
| CSAPLAN | SPSS Analysis Plan | 7 | |
| CSD | Csound file | 17 | |
| CSF | Cal3D Skeleton File | 4 | |
| CSF | Content Sealed Format | 8 | |
| CSH | Adobe Photoshop Custom Shape | 13 | |
| CSL | Citation Style Language | 6 | |
| CSM | CASL compiled PalmPilot program | 15 | |
| CSM | Motion Capture File Format | 125 | Alex Paven |
| CSO | CISO Compressed ISO CD image | 4 | |
| CSP | AudioZip encoded audio | 7 | |
| CSP | CASLwin executable | 15 | |
| CSPLAN | SPSS Sampling Plan | 5 | |
| CSPROJ | Visual Studio C# Project | 22 | Ryan Jones |
| CSW | Compressed Square Wave | 3 | |
| CT | CheatEngine cheat table | 5 | |
| CTB | AutoCAD 2000 Plot Color Table | 9 | |
| CTD | Sony ClickToDvd Project | 4 | |
| CTF | WhereIsIt? catalog file | 10 | fenixproductions |
| CTG | Canon Photo Info file | 12 | |
| CTI | Bitz and Pixels XML (ASCII)Report Template Info for collectorz.com products | 18 | Robert Williams |
| CTL | Phoenix Visual Designer third party control | 11 | |
| CTL | Visual Basic user-defined control file | 8 | |
| CTT | MSN Messenger Saved Contact List | 5 | |
| CTW | Context tree weighing (CTW) compressed file | 9 | |
| CTX | Gasteiger group CTX | 7 | |
| CUB | Isis Cube data | 9 | |
| CUB | SeeYou Airspace | 3 | |
| CUBE | Gaussian Cube data | 4 | |
| CUE | ISO CDImage cue/description - Data | 6 | |
| CUE | ISO CDImage cue/description - Data (with remark) | 8 | |
| CUR | Windows Cursor shape | 121 | |
| CURXPTHEME | CursorXP theme | 13 | |
| CVA | Compaq Diagnostics | 33 | |
| CVD | Clam AntiVirus virus database | 6 | |
| CVF | Jet-VoiceMail audio data | 3 | |
| CVG | Calamus Vector Graphic | 12 | |
| CVP | WinFax Cover Page | 7 | |
| CWD | Cardwar Cards deck | 8 | |
| CWK | Claris Works document | 13 | |
| CWK | Claris Works text (MacBinary) | 7 | |
| CWK | Claris Works word processor (MacBinary) | 7 | |
| CWP | Cakewalk SONAR project | 20 | |
| CWR | WrapCandy template | 11 | |
| CWS | Combustion v2 WorkSpace project | 6 | Alex Paven |
| CXF | CTXf compressed archive | 3 | |
| CXF | Picasa collage | 3 | |
| CYP | Crocodile Physics Simulation | 28 | |
| CZD | Crash Zone Drawing | 4 | |
| CZIP | ZipGenius encrypted compressed archive | 6 | |
