If your hand is empty, it can help you refill it, and if you already have lots of cards in hand, you can discard the bad ones and create some 1/1 tokens
Even as good as Regrowth is, Im more intrigued by a new printing from Kaladesh than I am by the good old-fashioned original, so lets start there: Ive had a copy of Recall in my Commander box for years now, and it has been thrown into many a deck along the way, only to always fall back out of it because discarding X cards and paying X mana twice is just not good enough for a multi-use Regrowth
Green Tron Green Tron is the most common type of Tron deck you will see
Setzer, Wandering Gambler Setzer, Wandering Gambler has hoops to jump through to flip coins on its own, but the real reason this card makes the list is the last sentence
Sorcery Color tag templates(None) Ramos, Dragon Engine Flying Whenever you cast a spell, put a +1/+1 counter on Ramos for each of that spell's colors