Quickbeam, Upstart Ent + Devoted Druid + Thopter Squadron + Maskwood Nexus

Quickbeam, Upstart Ent

Devoted Druid

Thopter Squadron

Maskwood Nexus

How it works

1. Activate Devoted Druid's first ability by tapping it, adding .
2. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
3. Activate Devoted Druid's first ability by tapping it, adding .
4. Activate Thopter Squadron's first ability by paying 1 and removing a +1/+1 counter from it, creating a 1/1 Thopter artifact creature token.
5. When the Thopter enters the battlefield as a Treefolk due to Maskwood Nexus, Quickbeam triggers, giving Devoted Druid and up to one other creature +2/+2 until end of turn.
6. Activate Thopter Squadron's second ability by paying 1 and sacrificing the Thopter, putting a +1/+1 counter on Thopter Squadron.
7. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
8. Repeat.

This ingenious loop uses Maskwood Nexus to turn all your creatures and creature tokens into every creature type—including Treefolk—which transforms every Thopter created into a trigger for Quickbeam, Upstart Ent. With Quickbeam pumping your team, Devoted Druid's self-untapping ability and mana generation fuel the loop. Meanwhile, Thopter Squadron provides the engine by converting mana and a +1/+1 counter into a token, then sacrificing that very Thopter to regain the counter and repeat the process indefinitely.