1mana monsters

Just to reiterate what I've said before, if we leave them ability-less, I think 9/29 (or 24/1) is probably a reasonable statline for a 1-mana creature.  Note that when you factor in card cost, they are ~80% as expensive as 2-mana creatures, which themselves are often pretty crappy.

Possible minor abilities:
Destroy [card]: Target monster takes 10 damage.

Target monster takes one damage.  (yes, I know this is useful against Radd-lifers/lifebars.  It should be useful for something)

Destroy [card]: Target monster gains 15 life until end of turn.

[card] loses this ability: Draw a card.

Into play: 50% chance of drawing a card.

Into play: A random monster you control takes 5 damage (on, say, a 28/1 one-coster)

Into play: A random monster your opponent controls takes 10 damage.

Into play: Your opponent takes 9 damage.

Into play: The bottommost [card] in your deck is placed on top.

Destroy [card]: Return target effect controlled by opponent to his hand.

Target monster gains 3 attack.

6: Destroy [card] and target effect.

Destroy [card] and target monster with 15% or less of its original life.

: Destroy [card] and target monster whose life is less than [card]'s attack.

Leaves play: Gain (1 mana of its color)

Make monster a 1-life 'lifebar' monster (no overflow damage)

Destroy [card]: Counter all abilities after this one (Speed C)