| ccg | GNOME C++ Source Code |
| ccn | Multimedia Fusion Compressed Data |
| cco | CodeCheck Object File |
| ccp | CodeCharge Studio Page |
| ccproj | Microsoft Azure Project |
| ccscc | ClearCase Source Control Info |
| ccx | Click and Create Extension |
| ccxml | CCXML Document |
| ccxml | TI Code Composer Studio Target Configuration |
| cdb | µVision Device Database |
| cdf | Amazon Lumberyard Character Definition Data |
| cdml | Claris Dynamic Markup Language Document |
| cdt | ProWorx NXT Temporary Long Comment Data |
| cdx | Alpha Five Table Index |
| cec | Windows CE Catalog Item |
| cel | CIMFast Event Language Source Code |
| cem | Windows CE Emulator Image |
| cesf | Ultra TC Editors Script |
| cet | Hitachi COBOL2002 Data |
| cetool | Windows CE Plugin |
| cfb | Microsoft Compound File Binary |
| cfc | ColdFusion Component File |
| cfm | ColdFusion Markup Language |
| cfml | ColdFusion Markup Language |
| cfo | Borland Turbo C Form Object |
| cga | CryENGINE Geometry Animation |
| cgf | Amazon Lumberyard Static Geometry Data |
| cgf | CryENGINE Geometry Format Data |
| cgf | ProWorx NXT Codegen Batch |
| cgfx | Nvidia CgFX Shader |
