The Dungeons & Dragons (4th edition) adventures published for PCs from level 21 to 30 are called Epic Tier Adventures.
From the PH: In the epic tier, your character’s capabilities are truly superheroic. Your class still determines most of your abilities, but your most dramatic powers come from your choice of epic destiny, which you select at 21st level. You travel across nations in the blink of an eye, and your whole party might take to the air in combat. The success or failure of your adventures has far-reaching consequences, possibly determining the fate of millions in this world and even planes beyond.