Imho:
Lyonar->Trinity oath (best draw card in the game)
Songhai->phoenix fire (removal and burn in one card)
Vetruvian->blood of air (similar to pf but different)
Magmar->makantor (no reasons needed here)
Abyssian->lure (board manipulation and ping)
Vanar->malicious wisp (ramp and sabotage)
Those cards can be put in any deck of their factions and perform great.
