tags which work on 4chan so you don't have to find out by yourself like i did:
[i] - italics [b] - bold [u] - underline [o] - overline [s] - strikethrough [#] - disables BBCode
[rem] - useless crap
[spoiler] - ...
[code] - ...
[sub] - subscript
[sup] - superscript
[m] - no idea what it stands for but I use it to decrease font size