Deadpool. Madcap is more powerful, but Deadpool is more skilled. Batman with a Green Lantern ring vs the Hulk with a Red Lantern ring.
Tie, they're off stage simultaneously by canes. In a race to kill the target, Altair vs Winter Soldier, Melee only
Winter Soldier. For all his abilities, Altair is still just a normal, unenhanced human. Steven Universe vs MLP for most toxic fanbase.
The Rancor. It's a little bigger, and has a longer reach. It's also, despite appearances, seemingly fast enough to grab a Jedi on high-alert. Ezra Bridger vs the Rancor.
Hulk, the ring would fly off a Atrocitus and choose Hulk as it's new bearer. Atrocitus lost his ring to Guy Gardner He'd definitely loose it to Hulk. Trump vs Captain Planet.
Trump is overweight, and I'm almost certain Captain Planet is ripped, so I'm going to have to give it to Cap. An ostrich sized fighter jet or a fighter jet sized ostrich?
The ostrich-sized fighter jet. Square-cube law states that as an object increases in size, its volume increases faster than its surface area. Thus, an ostrich with bones and muscles increased 100x would have a mass increased by 1000x - far too much weight to support. Therefore, the fight would end with a tiny toy plane buzzing triumphantly around a screeching, dying, broken mound of ostrich flesh. Damien Wayne vs Teen Titans Robin. (Presumably Dick Greyson)
While putting up a good fight, I'd give the edge to Alucard. He is a truly a one man battalion. And he can summon another battalion. To find and snipe the other. Caitlyn (League of Legends) vs Widowmaker (Overwatch)
Piper has a gun. Laser guns. Lasers are better then swords. Piper wins. The Tragedy of Darth Plagueis the Wise vs The Senate