Todomomo

We've already seen theirs. Frostbite and Burns, and anemia(Iron Deficiency)

Kirimina

Kirishima's organs harden and can pierce through his flesh

Mina's skin might Melt off

Miruhawks

They both go crazy during the spring

Iidamei

The engines can be pulled out and get very painful so sometimes he does it himself.

Mei loses more and more of her vision when she uses her quirk.

Kamijirou

Sometimes her earphones get a mind of their own and stab her in the leg and send her heartbeats into her own body (there is very graphic art for this)

Kaminari can get horrible shocks to the point he might as well be Dabi.

Dabi x Toga

Literally-

They are the malfunctions of their quirks.

Nejitama

Crazy.

Sometimes the food he eats manifest out of him against his will. An octopus tentacle might choke him out.

For her? She can fall out of the sky from a lack of stamina :/

Mt.Kamui

Idk. Her skin doesn't grow with her one time?

Kamui just vibes lmao

Ryushot

Scales grow on her body and the more she tries to pluck them, the more there are. When she peels them they bleed and her teeth get sharper to the point they pierce her lips.

Shinya's neck can go "Oop" if he uses his quirk on his neck. That's why he only goes from the neck down and all, and omg, his quirk freaks me out cuz I'm like "how flexible is this man"

HitoRei

Hitoshi ends up hurting his vocal cords :)

The objects she hold can get too heavy and can crush her.

Tetsukendou

Metal starts poking out of his flesh instead of becoming his flesh, ya know.

Kendou's bones pierce through her hands when they shrink back to normal size :).

SetSero

Sometimes her limbs don't come back

Sero, he chokes on tape?

Shintati

He loses his senses just like the kids, and he gets bad migraines.

Tatami, her limbs can get stuck inside her body.

Fatjoke

He don't really got one-

The more she uses her quirk, the more she goes insane. She either gets depressed, goes crazy, or she has the imaginary audience thing. I think the depression thing is a bit overused so I think the imaginary audience and going a bit crazy would be different but make less sense so idk.

Midotsu

His body should've snapped like Nighteye's spine when he got that quirk.

She can end up choking herself out, bet. Oh and she's a frog.

Kacchako

He rips apart, goes dead, and he could possibly lose his vision :/.

Ochako could float to the moon. Wait no, not Yue.

She can go to Mars.

Micari

She doesn't have a canon quirk but imma make one up for her.

So she has to be able to manage these demon spawn and I like to think her and Aizawa are cousins so that Aizawa is forced to go to the wedding. So version of the erasure quirk but possibly weaker. Like she can only erase one quirk at a time or her eyes burn.

So she can cry blood. The end. Oh and her vision gets worse and she needs glasses.

He's slowly going deaf and his throat kinda goes "uhhh no" whenever he uses his quirk.