For 3 mana, everyone gets some variation of life and/or cards (although typically cards are better
Rofellos, Llanowar Emissary 2.0 As two mana accelerators go this is about the most extreme in terms of potential
While Commander as a format has a great host of counter synergy, alongside older Hydras to benefit from them, those decks can often suffer from creating immense stacks of power and toughness without any way to actually benefit from them
Outside of just running this because its fun, I can see it being useful in decks like Pako, Arcane Retriever and Haldan, Avid Arcanist
Echoing Deeps Listed at: $8 Echoing Deeps goes great in decks that feature cave land cards like Forgotten Monument and Cavernous Maw
Amareth the Lustrous Buffs: Amareth, the Lustrous doesnt enhance Hare Apparent to be more threatening to your opponents in any direct way, but since each of them are now effectively scaling draw spells for two mana each, it doesnt really matter