This niche use has become very handy and popular across formats, including Pioneer, Legacy, and Cube
Green also has cards that check for a creatures power at certain phases of the game, like Sylvan Scavenging and Primal Empathy that get much stronger when pump spells ensure you meet the power requirements
5 Runaway Steam-Kin Can Generate Three Mana For Every Three Spells Mana-generating creatures are always pretty useful, and Runaway Steam-Kin is an absolute powerhouse in red decks with plenty of cheap spells
Often found in taverns and alehouses, she's the god of boasting and storytelling, a patron to the many skalds across the plane
Perhaps one of the most well-known and most played card that lets you do this is Aether Vial, a Modern all-star that you can tap to put a creature into play from your hand so long as that creatures mana value equals the number of charge counters on it, which you can choose to add at the start of your turn