Magneto Magnetic Translocation: Welcome to die!
Punisher Retribution: Boom! Headshot
Thor Mjolnir’s might: I smite thee
Hulk Smash: SMASH (sorry, I just can’t imagine him saying anything else)
Spider-man All Tied Up: Stunlock for you (repeat ad nasuim)
Juggernaught Headbutt: YOLO!!
OBW AR: “I’m the worst person ever”
Any Character Hmm did I hit too hard? I don’t want to be nerfed.
IM40 yellow: IMMA CHARGIN MY LAZOR
IM40 red: IMMA FIRING MY LAZOR
OBW blue: …fuckin Molotov Cocktail
Bullseye purple:
OBW Aggressive Recon: “I must break you.”
Punisher Retribution: “And shepherds we shall be, for thee, my Lord, for thee…”
Magneto Magnetic Translocation: “I’ve never met a man so tired of being alive.”
Human Torch Any Power: “200 degrees, that’s why they call me Mr. Fahrenheeeiiiiit!”
Captain America Any Power: “FLAME ON!..oh, wait.”
Bagman Any Power: (To teammates) “Sorry guys.”
Dr. Doom Technopathic Strike: "Does it come in black? 
"
Hulk Anger: “WHY HULK WEAR IMPRACTICAL METAL PANTS?!?!”
IM40 Unibeam: “I think she wants the Gallagher!”
I do not know what Lazy Cap says when he uses Star-Spangled Avenger. I just quietly whisper “Kabong!”
These are things I usually say to myself while playing:
Thor: Thunder Strike “INTERNATIONAL JOYHAMMER~!”
Thor: Mjolnir’s Might" “banghammer. Case dismissed.”
GSBW: Deceptive Tactics “Eeeee, buuuugs.” (/Bob Dylan voice)
Ares: Onslaught “Sexecutioner~!”
Ares: Sunder <> as his disembodied head rolls to the opponents and explodes
Magneto Classic: Magnetized Projectile: “I’m hoding your heart in my hand.”
Magneto Classic: Magnetic Translocation “Let. The tinykitty. Begin.”
Dr. Doom: Summon Demons “Ah, the music of the spheres.”
OBW: Aggressive Recon “I’ll take that, thankyouverymuch.”
Patch: Beserker Rage: “Now we go to work.”
CMags MagTrans: “Time… to redecorate.” (voiced by Ian McKellen, natch)
OBW Anti-grav: “F— physics.”
Hulk Anger: “HULK NEED BARF BAG!”
Punisher Retribution: “This pistol fires SUVs.”
CStorm Raging Tempest: “OWWWW! WELL SCREW YOU TOO!”
Psylocke Bewilder: “Soooo… you finished with that? It’s okay, I can wait.”
Clearly, I am extremely well-versed in Marvel lore.
Punisher Retribution: “And Shepherds we shall be For Thee my Lord, for Thee Power hath descended forth from Thy hand Our feet may swiftly carry out Thy commands. So we shall flow a river forth to Thee And teeming with souls shall it ever be. In Nomine Patri, Et Filii, Et Spiritus Sancti”
Oh wait, wrong movie…
I always imagine Lazy Cap singing his old cartoon song:
When Captain America throws his mighty shiiiiield
All those who chose to oppose his shield must yiiiiiiield!
I swear, I’ve been permanently earwormed with this ever since I put Cap into my regular rotation.
Whenever I use any move of either Thor AC/DC’s Thunderstruck goes through my head.
My main one is:
Doom Technopathic Strike:
CHANGE
(all the things guy)
ALL THE BLUES!
Sorry I couldn’t find a generator that was BBC-friendly, you’ll just have to imagine it 
Ares: RRRAAARRRGGGHHH
Every time you watch Falcon soar, you will now hear Steve Miller Band’s “Fly Like an Eagle”
https://www.youtube.com/watch?v=c1f7eZ8 … lpage#t=49
you can all thank me later, when the screaming stops.
Love the creativity! This is great stuff!
I only have one for Pun’s Retribution. Always in my best James Bond villianesque voice, “Goodbye, Mr. Xxxx”. I do it ever, single, time. 
For Storm’s R: “COME FORTH GAIA! BY THE POWER OF THE WINDS!”
(UMvC3 FTW)
I imagine “Don’t mind if I do”.
Now this is stuck in my head.
Sort of on topic, but whenever I get a monster cascade I gleefully imagine the AI throwing its phone at the wall and yelling “this is TINY KITTY!” 
And Moonstone’s Photon Blast looks like she’s going to say, “Tickle Torture!”