Todoroki (with some nudging from Kirishima and Kaminari) quotes vines frequently.

Examples of some of his favorites being;

Todoroki at any given opportunity: “Hey~ How you doing? Well I’m doing just fine; I lied, I’m dying inside~”

Kaminari: “No one told you life was--!”
Todoroki: “...Gonna be this gay.”
The whole class: *claP CLAP CLAP CLAP*

Todoroki: *says “oh no” when something genuinely goes wrong*
Kaminari: “Oh no!”
Kirishima, in his best Kool-Aid Man voice: “OH YEAH”
Todoroki: “pfft--”

Kirishima: “...” *comes up right next to Todoroki’s ear* “the appendix was most likely burst due to pressure during sex”
Todoroki: *dramatically turns* “sex”

Kaminari: “Welcome to McDonald’s, how are you doing tonight?”
Todoroki: “I wanna fucking die.”
Midoriya, out of nowhere: “Same.”

Todoroki before he pours any beverage into a cup: “Two shots of vodka.” *pours the entire drink into the cup*

Ashido: "Oh my god, look at that face~!"
Todoroki: "If you're feeling suicidal, you've come to the right place."

•∆•
To be updated in future chapters. He has a lot of favorite vines.