Many of them support coop. You'll have to check their readmes. If coop is supported, it is most likely mentioned.

If you doesn't afraid of anything, get a netquake client with autodownload (qrack, darkplaces, Baker's engineX) and connect to flanders.quake1.net:26001 for online coop, really fun to play!

Yeah, but before you do go online to play coop, make sure you install the proper mappack or you're downloading/disconnecting etc. forever. I think QuakeOne.com has all the links to these things I think...

Honey is beautifull, but then i tried Unforgiven! OMG! it's fantastic! huge horde of enemies, very very big castles, new textures, new enemies, very fast action. The best single player maps i found so far..

how can I reduce/turn off underwater fog in quakespasm?

No idea.

New map by than, a remix of the id classic DM7:

http://www.quaddicted.com/reviews/dm7rmx.html
http://www.quaddicted.com/reviews/dm7rmx.zip

(Edited 2012-05-07, 17:02)