Collision of Realms

Each player reveals and puts onto the battlefield one creature card or fewer. They don't reveal a card for each nontoken creature they shuffle into their library; it's just one creature card at most.

All creatures are shuffled into their owners' libraries at the same time. Then all players who shuffled nontoken creatures into their library this way reveal cards. Then all creature cards revealed this way enter the battlefield at the same time. Then all other cards are put on the bottom of their owners' libraries. Any abilities that triggered during this process are then put on the stack, starting by those controlled by the active player in an order of that player's choice, then continuing with each other player's abilities in turn order. The last player to put their abilities on the stack will be the first player to have their abilities resolve. A player who controls no creatures or who controls only creature tokens will still shuffle their library.