Timing restrictions based on its types are ignored
Whenever a creature is destroyed (either from a "destroy" effect or from damage), you may activate the regenerate ability (in this case, sacrificing a creature), tap the creature, and remove it from combat (if it's in combat)
Its uniquely strong in a deck that can clear its path with discard spells and protect it with a healthy suite of creatures and removal spells
The Selesnya four-drop has first strike, trample and a 4/4 and then has an ETB ability to search your library for two cheap artifact, dork or enchantment cards and toss them into your hand
Flintheart Glomgold Lone Cheater By now, so many characters have an ability that makes them Evasive during your turn that the ability itself should almost be its own keyword ability
Peak Value: $4,000$6,000 USD (est.) (PSA 9) Why It's Valuable: One of the most powerful lands ever printed, allowing a player to draw an extra card each turn