| Modern Pinball | | - | |
| Modern Toolbar Icons | | - | |
| Mongrel | | - | |
| Mosaic-Fox | | - | |
| Mostly Crystal | | - | |
| Moxxi | | - | |
| Mozilla.org | | - | |
| Myzking | | - | |
| N2Scape | | - | |
| NASA Night Launch | | - | |
| NASA Night Launch(724448) | | - | |
| NASA Normal | | - | |
| NEWA | | - | |
| Native XP | | - | |
| Nautical Classic | | - | |
| Nautipolis | | - | |
| Netscape Navigator Nostalgia | | - | |
| Netscape Windows 3.1 | | - | |
| Noia 2.0 (eXtreme) | | - | |
| Noia 2.0 (lite) | | - | |
| Noia 4 | | - | |
| Noia Fox | | - | |
| Nuri | | - | |
| Nuvola FF | | - | |
| N－Scape1 | | - | |
| Office Black | | - | |
| OldFactory | | - | |
| OldFactory Black | | - | |
| Onyx | | - | |
| OpenWorld | | - | |
| OpenWorld_Win | | - | |
| OrangeShift | | - | |
| Orbit Blue | | - | |
| Orbit Grey | | - | |
| Orbit Grey Custom | | - | |
| Orbit Orange | | - | |
| Orbit Yellow 2006 | | - | |
| Orthodox for Firefox | | - | |
| Outlook 2003 Blue | | - | |
| Outlook 2003 Green | | - | |
| Outlook 2003 Silver | | - | |
| Oxygen KDE | | - | |
| Past Modern Revisited | | - | |
| Past modern revisited，reloaded | | - | |
| Penguin | | - | |
| Phoenity Firefox | | - | |
| Phoenity Modern | | - | |
| Phoenix Simple | | - | |
| PimpZilla | | - | |
| Pinball Compact | | - | |
