These are ideas for boards I find in the 2006-2008 4chan archive (though mostly /b/). It includes both individual boards while also including plays on already existing boards.
/gy/ - Gay - Said in this thread here in which the OP said that there needs to be gay board or else he will keep posting gay porn to /b/. Someone else said that "i support a /gy/ if its only bishies".
/desu/ - Desu - Said in this desu sticky, in which an anti-desu poster requested the board /desu/ to be made, and anyone who uses Desu off that board to be banned (which is kind foreshadowing of /mlp/ and GR15).
/b/ - Gay - Said in this thread here in which the OP said that there needs to be gay board or else he will keep posting gay porn to /b/. However, /b/ seemed to be enjoying the porn, causing some to joke that /b/ IS the gay porn board.
/b/ - Superior, /b/ - Sack of Shit - Said in this thread here as they were given as examples to what /b/ once was and how it now was as it had "fallen from grace".