| Extension | File Type | Files scanned | Contributor |
| K7 | DCMO6 emulator tape image | 10 | |
| KA | Karma Asset | 6 | |
| KAL | Hondata K-Manager Calibration data | 9 | |
| KAP | MapInfo Sea Chart | 6 | |
| KAR/MID | Karaoke MIDI | 186 | |
| KAT | Katorzer music | 2 | |
| KAW | Karma Workspace | 4 | |
| KCF | Sony Ericsson remote control configuration | 6 | |
| KCH | KChess saved match | 8 | |
| KCM | KonyvCalc file | 4 | |
| KDB | Doobs database | 1 | Miguel Vanhove |
| KDB | KeePass Password Safe database | 5 | |
| KDB | Kinetica data | 8 | |
| KDH | KDH document | 22 | |
| KDX | Google Earth import definition | 5 | |
| KEXI | Kexi database | 4 | |
| KEY | H-BEDV - AVIRA product key | 6 | |
| KEY | Kaspersky Lab Key file | 6 | |
| KEY | QBX (MS Basic 7.x) Editor keyboard definition | 4 | |
| KFN | KaraFun Karaoke Song | 21 | |
| KGB | KGB Archiver compressed archive | 9 | Edgaras |
| KGB | Kremlin Encrypted File | 10 | mishka |
| KID | Kidspiration file | 14 | |
| KIF | KIFF - Kt Interchange File Format compressed bitmap | 11 | |
| KIN | Kinemage protein language | 26 | |
| KLA | KLARFF map-data | 6 | |
| KLIP | KlipFolio Klip | 27 | |
| KML | Emu48 keyboard configuration | 9 | Renan |
| KML | Google Earth network link | 12 | |
| KML | Google Earth placemark | 6 | |
| KML | Google Earth placemark (Unicode) | 7 | |
| KMP | Korg Trinity/Triton multisample | 8 | |
| KMY | KMyMoney XML data (decompressed) | 4 | |
| KMZ | Google Earth saved working session | 13 | |
| KNT | KeyNote notes | 2 | |
| KOA | Koala Paint (C64) bitmap | 8 | |
| KOZ | Sprint Music Store audio | 5 | |
| KPL | Kazaa Playlist | 25 | Joystick |
| KPR | KOffice KPresenter Presentation | 6 | |
| KPX | Kid Pix project | 30 | |
| KRAW | kRAW Audio Stream | 3 | |
| KRIS | Kris Tracker / ChipTracker song/module | 2 | |
| KRZ | Kurzweil 2000 sample | 5 | |
| KSC | Korg Trinity/Triton script | 3 | |
| KSF | Korg Trinity/Triton sample | 112 | |
| KSL | Karaoke Song List Creator song list | 3 | |
| KSM | Kefrens-Sound Machine song/module | 2 | |
| KSV | Kheops Studio Video | 4 | |
| KTS | KT-Tech compressed audio | 4 | |
| KW3 | KanjiWORD document | 6 | |
| KWD | KWord document | 10 | |
| KWO | KeyWallet Object - encrypted data | 8 | |
| KWS | KeyWallet Skin | 4 | |
| KXS | Kexis lossless compressed audio | 2 | |
