Useful BBCodes

[Mr. X]

 [plain] [/plain]

Allows you to put stuff in that box and it won't trigger any type of exisiting bbcodes and screw stuff up. Remove the space in the last bracket.

 [media=ytplaylist] [/media]

Allows you embed YT Playlist like so

Spoiler

 [av] [/av]

Allows embeding .webm

Spoiler

[av]http://a.pomf.se/vixfnq.webm[/av]

 

[Vadsamoht]

Also worth noting that there's a list of most of the less common BBCodes in the help section (here).