I'm participating in a league right now, and there is an achievement for playing team games. I did one last week paired with a Ret player. I played a Vindictus infantry and solo list and it worked out ok, but I found I wasn't really bringing much to support my partner.
Do we have a caster who does support a partnered team as well as our own?
Harby is about the only one I can think of off the top of my head. Her feat in particular. I suppose pKreoss, too, with his pop and drop and toolbox of spells.