Fear of Missing Out and Splinter Twin on the battlefield (Splinter Twin attached to Fear of Missing Out).
Fear of Missing Out does not have summoning sickness.
There are four or more card types among cards in your graveyard.
Steps
Activate Fear of Missing Out by tapping it, creating a token copy of it with haste.
Declare the Fear of Missing Out token as an attacker, triggering its ability, untapping the nontoken Fear of Missing Out and causing you to get an additional combat phase after this one.