http://www.bloodbowl-game.com/Here you can find a Breakdown for Human, Ork, Chaos, Wood Elf, Goblins, Skaven, Dwarfs and Lizzardmen.
All Elf Team have a high agility. So the are equal fpr Pass-Playing.
Wood Elf are the fastet one. And the only one with a Big Guy (Treeman)
Dark Elf are the BAD one. (Assassin)
High Elf have the best AV.
The Normal Elf are Normal.
Amazons are a Moving Team. All Amazones have Dodge. So the can TRY to move during enemy Tackling Zones (exept Dwarfs)
Kemri, Necromant and Undead
Slow and forget passing. But the are tough. And thanks regeneration you lost rarely a Player.
Norse
Humans with Block. If you want play first the Enemy head and then with the Ball, there are the right Team.