| key | SmartWare Database Key File |
| key | Tinker Keyword Parameters |
| key | Windows Registry Key Data |
| keychain | Mac OS X Keychain |
| keyhelp | UltraEdit Keyhelp Data |
| keyhelp | Zoom Player Keyboard Macros Data |
| keylist | UltraEdit Keylist Data |
| keylist | Zoom Player Virtual Keyboard Layout |
| keyring | Java Key Store |
| keystore | Java Key Store |
| keytab | Kerberos Encrypted Key Data |
| kez | CA 01 Customer Product Numbers Data |
| kfl | IRIS Literary Data |
| kfl | Kwalitan Filter Data |
| kfl | Pegasus Mail Auto-reply Memory Data |
| kfo | Konica Minolta Bizhub Copier Overlay Data |
| kfp | Adobe Acrobat Preflight Profile |
| kfr | Kalles Fraktaler 2 Data |
| kfs | Pegasus Mail Static Kill Data |
| kft | Matrox X.Tools Keyframe Data |
| kfx | Kofax Capabilities File |
| kgf | UniCERT Key Generation Data |
| kgm | KeyTERRA-FIRMA Ground Model Data |
| kgs | Kogeo Session Data |
| kgtemp | KuGou Temporary Cache Data |
| kh | Khmer-Protocols Hash Table |
| khd | Microsoft Dynamics AX Kernel Help Documentation |
| khe | kHED 3D Model Data |
| khf | Kwalitan Tree Structure |
| khs | Kwalitan History Data |
