| .modpkg |
Minecraft Pocket Manager File |
| .mcaddon |
Minecraft Pack Addon File |
| .mctemplate |
Minecraft World Template |
| .notebook |
SMART Notebook File |
| .nco |
Nero BackItUp File |
| .nth |
Nokia Series 40 Theme File |
| .nbm |
NetBeans Module |
| .nfl |
Nokia Flash Lite Package |
| .nw |
Node-Webkit App Package |
| .nar |
Nexon game archive |
| .n2 |
Nitrous Minecraft GLSL Shader File |
| .noy |
NOY Backup File |
| .odt |
OpenDocument Text Document |
| .odp |
OpenDocument Presentation |
| .ods |
OpenDocument Spreadsheet |
| .osz |
Osu! Beatmap File |
| .odf |
OpenDocument Formula |
| .oxt |
Apache OpenOffice Extension |
| .odb |
OpenDocument Database |
| .oam |
Adobe Edge Animate Widget File |
| .osk |
Osu! Skin File |
| .otc |
OpenDocument Chart Template |
| .odi |
OpenDocument Image |
| .oti |
OpenDocument Image Template |