I uhh honestly don't really know many.
For 2v2 here's some good pairs that I know.
Hunter+Druid-resto
Paladin-holy+Rogue
Shaman-resto+Rogue
Shaman-resto+Shaman-Elemental
Paladin-holy+Warrior
(dun know shit about 3v3's)
5v5's
Paladin-Holy+Paladin-holy+Warrior+Warrior+Warrior
Paladin-Holy+Priest-holy+Shaman-Elemental+rogue+rogue
Paladin-Holy+Priest-holy+Shaman-Elemental+Druid+Druid
Paladin-Holy+Priest-holy+Shaman-Elemental+Mage-Fire+Hunter
(have more but feel like shit so I'm done for now)