Ayara, First of Locthwain makes an excellent black commander as it converts all your sacrifice fodder into life loss for your opponent and lifegain for you, then card draw
You know when to board wipe based on these important considerations: How many creatures are you removing, how much danger are you in, and do you benefit
Yes, you have keep them on the board for a turn before they can do anything, but hey, I think it's worth it as a great budget option until you can afford something a little pricier
#7 Ichor Rats Ichor Rats is technically a creature, but you play it for the ETB
Remember that you are not forced to play three or four copies of the same card
(Each in the mana costs of permanents you control counts toward your devotion to blue.) Creature - Wizard Merfolk The One Ring Indestructible When The One Ring enters, if you cast it, you gain protection from everything until your next turn