Complete rebuild of Upgrayedd.
Our plan is to run only a few very powerful creatures in a deck that is otherwise on a token creature plan, so we can Mass Polymorph our tokens into a brutal alpha strike.
On the theory that an overwhelming finisher like this isn't really needed in a control deck, we are instead going with an aggressive plan making tokens and ramping at the same time, trying for a turn 4 blowout and often settling for turn 5. Since we're ramping anyway, we might as well manafix at the same time so we can play the needed for Mass Polymorph and the needed for "creatures you control have haste" as splashes. Khalni Garden + Springleaf Drum
is our ideal opener. Careful Cultivation doesn't manafix but doubles as one of our token generators and can turn Populate into ramp. Farseek with Idyllic Beachfront, Molten Tributary, and Sacred Peaks lets us get multiple colors at once.
Meanwhile our main token builders are Raise the Alarm, Chatter of the Squirrel, and Sprout Swarm. Sprout Swarm is great because we can often cast it with buyback the turn before we Mass Polymorph and then cast it again for free on the turn we do. Note they are all instant speed except Chatter of the Squirrel. Our interaction is also instant speed, so we tend to tap out on the first few turns to ramp and on the turn we Mass Polymorph to hopefully end the game, but in between we have some turns where we can leave interaction up before we commit to growing our token stock in case a more linear deck goes for the kill. That's where Rootborn Defenses, Sundering Growth and Volcanic Spite come in. The first two populate, so we're still advancing our plan if we have to interact, and Volcanic Spite has the very useful ability to tuck a creature back into the library where it can be hit with Polymorph instead of sitting in our hand waiting for hard-cast.
Our main payoff is two Trostani's Summoners. Much as I like Pelakka Wurm, Trostani's Summoner being on-plan with our token strategy makes the deck more resilient - if the ramp part succeeds but the tokens get wiped out or we just don't draw the token generators, then Trostani's Summoner can function as an input just as well as an output once we can afford to cast her. However, we only have room for two because even just one is generally enough and we want to buff the team: Archetype of Endurance and Archetype of Imagination get all the power we dump on the field heading into to our opponents' life totals instead of into chump blockers or removal. Keldon Strike Team gets that train on the rails immediately and like Trostani's Summoner also doubles as an input if necessary. Any four of those five creatures can take out one opponent and all five might be enough to take out two in multiplayer - 32 total power in the air. That's all the creatures we'll play; anything beyond five and we're just diluting our speed and ruining the consistency of our payoff.
One nice benefit of taking a ramping rather than controlling strategy here is that if Mass Polymorph gets answered, we're not too far from being able to hard cast our creatures anyway. So, rather than attempting to beat control decks at their own game trying to protect Mass Polymorph, instead we'll include one copy of Heroic Charge as a backup finisher.
