Beyond that, there are so many decks that care about keeping their Commander in play that this card will be good forever
That's perfect for elves, goblins, wizards, knights, warriors, and yes, even Slivers

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What cards are similar to Elvish Regrower
Lets assume you have a beefy creature on the battlefield, and lets be honest, in green that should be pretty easy
Some tournaments may also have tournament specific rules which will either be announced to you in a player briefing before the tournament starts or it will be in the rules when you sign up