Timestream Navigator + Progenitor Mimic

Timestream Navigator

Progenitor Mimic

How it works

1. At the beginning of your upkeep, Progenitor Mimic triggers, creating a copy of Timestream Navigator.
2. Activate the ability of any Timestream Navigator that has not entered this turn by paying 2, tapping it, and putting it on the bottom of your library, taking an extra turn after this one.
3. Repeat each turn.