lainchan on rare occasion but it pisses me off too much (;´Д`)
then there's nashi and prodefch but I found out about both from here

used to mostly to go on 4chan if I'm honest, haven't been much of an alt-chan guy in ages
dropped 4chan because it's shit and no one wants to actually talk about anything

very long ago, I used to go on 7chan, 711chan, renchan (long gone loli board), iichan, and a few others I can't remember right now
(´人｀)