In "Saving The People Who Save People" The fight between Megahertz and Tecton.
Skylar taking on Megahertz, despite not having any of her powers.
By the same token, Kaz and Oliver trying to stall him when it becomes clear Skylar won't last for long. Very impressive considering they're both normal humans and teenagers.
Oliver knocking Kaz to the ground and holding him in a leg lock in "I Normo." Kaz may be the hero, but considering just how much a jerk he had been towards Skylar and the fact he was willing to start a (mostly fake) fight with his best friend all to impress a shallow air head, he had it coming.
Kaz and Oliver being willing to give their lives to save the earth from a mess they created in "Pranks For Nothing." Admittedly it was all a prank, but the heroism still there.
It was also a very impressive prank as well.
Alan digging through the rubbish to save a little girl in "Pranks For Nothing", with only one minute before they were all disintegrated, the guy might be a jerk, but he still put her before himself.
Oliver figuring out a way to manipulate the powers of a hero who could see the future to stop time when they needed a few more minutes.
Skylar, Kaz and Oliver defeating the Crimson Demon, Skylar does most of the work, but once again they were all very brave and the fight is great to watch, complete with slow motion.
Kaz and Oliver giving Skylar night vision goggles before turning off the lights (No one from her planet can see in the dark) then we see her owning Experion.
Captain Atomic's fight with Black Falcon was AWESOME!
Oliver managing to punch out a mutated Man-shark with one punch, to save Alan in "Are You Afraid of the Shark."
The Season Finale has quite a few one being Alan Tackling Catastrophe before he could kill Horace.
Then there was Skylar tricking the Annihilator with a hologram.
Not to mention the fight between Megahurtz and Experion Vs The Crusher, Owl Girl and Gray Granite.
The Annihilator himself gets one, for being smart enough to prepare for the possibility he was defeated and altering Skylar's powers, so she would turn evil and be his slave. Meaning regardless of the outcome of their fight he would be the victor.
The season Premier has several:
Horace gets one for managing to stall the villains attempts to find the chip holding the super heroes details for so long, through a variety of reasonably impressive methods, to stop them being able to torture him for information.
Titanio leading a small army of heroes into Mighty Med to defeat the Annihilator.
The fight between the Annihilator and Skylar, and Titanio and the other heroes. Highlights include the Annihilator vs Titanio, and Skylar vs Alley Cat.
Skylar snatching victory from the jars of defeat at the end, by remembering what Kaz and Oliver said earlier about Rewind's powers.
Skylar Vs Tecton in "Lair, Lair."
The Annihilator Vs Hapax in "Storms End"
Oliver pulling a brilliant I Surrender, Suckers moment on Skylar by seemingly joining her and then betraying Kaz and Hapax to prove it, but the moment Skylar lets her guard down, Oliver pulls a lump of coal (Skylar's only weakness) from his backpack and weakening her to the point Hapax can drain her powers.
In a twisted way The Annihilator gets one for Managing to actually kill Skylar (thankfully She gets better), talk about cementing Knight of Cerebus.
Horace, of all people, gets one in "Storm's End". When Skylar dies from Annihilator's dying blow despite Kaz and Oliver getting her back to Mighty Med, Horace reveals his Secret Identity as Caduceo, immortal healer of superheroes, and uses his powers to bring Skylar back to life.
Oliver and Skylar, defeating Ambush with a literal Dance battle.
Kaz (empowered with key of Steel) Vs Slaughter Master.
The fight scene in "Its A Matter of Principal", props for including so many people in the fight: (not all at once) Captain Atomic, Skylar, Oliver, Kaz and Stefanie...Yes Stefanie sure she only hits the android with her shoe, but even that counts as something.
In "Living the Dream", Oliver and Tecton go to save Kaz from a villain's two lackeys, arriving Tecton takes them on. Part way through the fight they manage encase him in sort of quick drying concrete foam, and hurl him out of the window (there on the top floor of the building) only for him to break free in mid air and fly back, without even bating an eyelid. At this point they both wisely run for it.