Preston, the Vanisher | Phyrexian Altar | Nature's Rhythm (and one other card)

Cards

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

Cast
Nature's Rhythm by paying at most ({3} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) , searching your library for
Fiend Hunter and putting it onto the battlefield.
When
Fiend Hunter enters, it and
Preston trigger.
Resolve the
Fiend Hunter trigger, exiling another creature if needed.
Resolve the
Preston trigger, creating a token copy of
Fiend Hunter that is a 0/1 Illusion.
When the
Fiend Hunter token enters, it triggers, exiling the nontoken
Fiend Hunter.
Activate
Phyrexian Altar by sacrificing the
Fiend Hunter token.
When the
Fiend Hunter token dies, it triggers, returning
Fiend Hunter from exile to the battlefield.
Repeat from step 2.

You can either cast
Nature's Rhythm from your hand or for the harmonize cost, adjusting mana requirements accordingly.

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