Spoiler: The Heralding StormQuite a powerful storm win condition. If you have a creature that can get through, this will give it +3/+3 that turn per storm count, then +2/+2 on following turns. However, I really like backup on a non-creature, and exalted is a good keyword to pair with it because it works the same on creatures and non-creatures. Storm and Exalted also work well as one of the only stacking keywords.
Spoiler: Arc BinderMy only real problem with this is the Phyrexian mana making it free. Other than that, backup and modular are cool together, although some people might misplay and also put the modular counters on the backup target. One issue with modular is that it only targets artifact creatures, but this makes things into artifacts. It all hangs together very well, but would probably kill your opponent too fast.
Spoiler: Rats of the Shadowflame
Spoiler: Uzu, the Shadow StormThis can get out of hand fast. At first I didn't realize that the ability needed to be activated so that you don't have exponential experience counter growth. It really penalizes the whole table for having one player who doesn't develop a board. It's not broken because it's still a 1/3 that dies to removal.
Spoiler: Corner on the Stand
Spoiler: WinnerThis was a really creative round. It was close, but I have to give it to The Heralding Storm by JNAProductions. While it probably needs to be toned down a bit, all three mechanics work together in exactly the way I was looking for.