+shuffle, +and, +owners', +libraries (5)
Flash
Vigilance
When Floodpits Drowner enters, tap target creature an opponent controls and put a stun counter on it.
, : Shuffle Floodpits Drowner and target creature with a stun counter on it into their owners' libraries.
Defender, flying
: Put Gomazoa and each creature it's blocking on top of their owners' libraries, then those players shuffle.
Shuffle Serene Remembrance and up to three target cards from a single graveyard into their owners' libraries.
, : Put Void Stalker and target creature on top of their owners' libraries, then those players shuffle their libraries.
: Put Vortex Elemental and each creature blocking or blocked by it on top of their owners' libraries, then those players shuffle.
: Target creature blocks Vortex Elemental this turn if able.
Gatherer works better in the Companion app!
, 
: Shuffle Floodpits Drowner and target creature with a stun counter on it into their owners' libraries.