Lagrella, the Magpie | Sun Titan | Preston, the Vanisher

(and one other card)

Cast
Essence Flux by paying ({U} magic symbol) , blinking
Lagrella.
When
Lagrella enters the battlefield, it and
Preston triggers.
Resolve the
Lagrella trigger, exiling
Sun Titan until
Lagrella leaves the battlefield.
Resolve the
Preston trigger, creating a token copy of
Lagrella that is a 0/1 Illusion.
Put the nontoken
Lagrella into your graveyard due to the legend rule.
If
Lagrella is your commander, choose not to return it to the command zone from your graveyard.
When
Lagrella leaves the battlefield,
Sun Titan is returned to the battlefield from exile.
Sun Titan,
Lagrella and
Preston each trigger.
Resolve the
Preston trigger, creating a token copy of
Sun Titan that is a 0/1 Illusion.
When the
Sun Titan token enters the battlefield, it triggers, choosing to return nothing to the battlefield.
Resolve the
Lagrella trigger, putting two +1/+1 counters on the nontoken
Sun Titan.
Resolve the
Sun Titan trigger from step 8, returning
Lagrella from your graveyard to the battlefield.
Repeat from step 2.