Izuku "No I'm not summoning them Mineta."

Izuku loved his quirk. Sure it drains his energy if he keeps it active too long but being able to summon characters from manga he has read and fighting along side them is cool! Of course a downside he found out when he was searching for new manga to read in the bookstore was that it includes, ahem, adult manga. Which while yes, he did obtain the ability to summon the characters there, since it requires him to know a lot about the character and read the manga, he decided to never summon them as he doesn't have the ability to control the people he summons. Of course when Mineta asks if his quirk includes erotica manga, Izuku tells him he isn't summoning any of the characters.

Basically Izuku has the ability to summon manga characters. Izuku has no ability to control the characters he summons so he sticks to good guys. It also has to be a professionally published manga to count as well. Depending on the strength of the character depends on how long Izuku can keep them summoned. For example he can summon and keep Goku around for a few minutes while he could have manga Red, and his Pokémon, around for almost an hour.