Alongside a graveyard-matters Golgari commander, Underrealm Lich and Altar of Dementia can get many cards into your graveyard quickly for the commander to be exponentially buffed with menace
Like Abe's Deck of Happiness and Joy, my signature multiplayer deck with a few thousand cards, this card is wonderful, since its huge defense makes it, usually, better than a Cho-Manno, Revolutionary since it's hard to crack 10 toughness and it sucks up all of the damage from a 8/8 trampler like an Aggressive Mammoth or a Terra Stomper
There are so many favorites for so many different reasons, but if I had to choose one it would be Scrabbling Skullcrab by John Tedrick
7 Autochthon Wurm Autochthon Wurm is a Selesnya wurm that costs a staggering 15 mana
Even if you favor one color over the others, it doesnt stop you from introducing dual-colored or multicolored cards that can make a difference
That is, undoubtedly, a powerful effect