You should always be locked into elves. Unless you get something like one of the Ones. Beasts aren't a bad choice if you manage to first pick a Cliffs (pretty sure that's Onslaught) but you often end up taking a bunch of elves because of mana.
If you aren't Elves, you probably want to aim for Beasts or Zombies. Zombies have a one, a powerful "tap five" lord, the trailblaizer for evasion, and reach (Shepherd of Rot) as well as a board wipe effect.
Like, we saw what was probably the best Soldier card earlier (Catapult Master) but soldiers aren't that great. Wizards have a One, but a lot of Wizards are lackluster, like a lot of blue creatures back in that day. They however have a number of Mistform creatures (changelings, sorta) and Imagecrafter, which is a strong effect in this format.