Preston, the Vanisher | Sister Hospitaller | Blasting Station (and one other card)

Cards

({6} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) at most available.

Cast
Chord of Calling by paying at most ({6} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) , searching your library for
Sister Hospitaller and putting it onto the battlefield.
When
Sister Hospitaller enters, it,
Blasting Station and
Preston trigger.
Resolve the
Blasting Station trigger, untapping it.
Resolve the
Sister Hospitaller trigger, returning an applicable target from your graveyard to the battlefield.
If you returned a creature in step 4,
Blasting Station triggers, untapping
Blasting Station.
Holding priority, activate
Blasting Station by tapping it and sacrificing
Sister Hospitaller.
Resolve the
Preston trigger, creating a token copy of
Sister Hospitaller that is a 0/1 Illusion.
When the
Sister Hospitaller token enters, it and
Blasting Station trigger.
Resolve the
Blasting Station trigger, untapping it.
Resolve the
Sister Hospitaller token's trigger, returning
Sister Hospitaller from your graveyard to the battlefield.
Repeat from step 2.

This combo has been estimated to be Exhibition (Bracket 1+).