Yannik, Scavenging Sentinel + Leonin Relic-Warder + Oblivion Ring
Yannik, Scavenging Sentinel
Leonin Relic-Warder
Oblivion Ring
Infinite creature ETBInfinite creature LTBInfinite +1/+1 counters on creatures you control
How it works
Cast Oblivion Ring by paying 2.
When Oblivion Ring enters the battlefield, its first ability triggers, exiling Yannik.
When Yannik leaves the battlefield, Leonin Relic-Warder returns to the battlefield from exile.
When Leonin Relic-Warder enters the battlefield, its first ability triggers, exiling Oblivion Ring.
When Oblivion Ring leaves the battlefield, its second ability triggers, returning Yannik from exile to the battlefield.
When Yannik enters the battlefield, it triggers, exiling Leonin Relic-Warder until Yannik leaves the battlefield and putting two +1/+1 counters on any creature you control.
When Leonin Relic-Warder leaves the battlefield, its second ability triggers, returning Oblivion Ring from exile to the battlefield.