It’s disappointing that the clans didn’t get big splashy seven-mana spells, so I thought I’d take a stab at them.
Put three +1/+1 counters on each creature you control. Creatures your opponents control get -X/-X until end of turn, where X is the greatest toughness among creatures you control.
Exile the top seven cards of your library. Until end of turn, you may cast noncreature cards exiled this way without paying their mana costs. For each spell cast this way, creatures you control get +1/+1 until end of turn.
Each player puts the top four cards of their library into their graveyard. Put up to three target permanent cards from graveyards onto the battlefield under your control.
Put any number of creature cards from your hand onto the battlefield. Those creatures gain deathtouch, haste, and lifelink. Return those creatures to your hand at the beginning of the next end step.
Destroy all noncreature, nonland permanents and all nonbasic lands. Draw a card for each permanent destroyed this way.
Any alternate ideas/developmental tweaks/general feedback?