I'll start with Harsh Mentor
Im pretty sure that this is on average, between a 3/3 and a 4/4, which isnt a bad place to be for two mana, especially if your cube has a lot of ways to create bonuses for this bunny (like token generation)
Muldrotha, the Gravetide (20k decks, #24, 58k more, $12) Top graveyard-based commander, great art
Counterspell The de facto Counterspell and the original one
It's simple: all of your creatures and lands are separate, but you each share the same 30-point life total and take your turns simultaneouslyplus you can block for each other too
It's effect is on-going, and you can build around it with artifact creatures or things you can't target (like Protection from Black) or indestructible stuff that can't be destroyed at all