Ron Perlman was the original onscreen Hellboy when the film came out back in 2004, but with the franchise rebooting, the mantle of the Right Hand of Doom was (reluctantly) passed on to David Harbour. When it comes to superhero movies, Perlman laments that Hellboy would probably be his last comic role.
Talking to ComicBook about potential heroes that he could play in the future, Perlman answers, "No, there's no comic book character that I have identified that I'm dying to play. Plus, I don't know if, at 68, I should even be educating the notion of superheroes anymore."
With Perlman's age, I would guess that he would be perfect as supporting characters in a franchise like the MCU. Michael Keaton was still able to play the Vulture, so I guess Perlman could have the energy to take on a role like the new Doctor Octopus, or maybe even just a voice role (he played Slade in the Teen Titans cartoon).
Heck, he could even go for a mo-cap role. Hellboy may be out of the question, but what if Perlman was cast as the Demon Etrigan for the DCEU? What about Gorilla Grodd in a future Flash movie?
Just recently Perlman has said that the reboot of the Hellboy franchise is still an ‘open wound' for him, but there's no use dwelling on that. Besides, if the movie fails, and Lionsgate sees that people actually loved the del Toro movies, maybe they'll greenlight a third film so Perlman and del Toro could finish what they started.
Catch the Hellboy reboot when it comes out April 12, 2019.
See Also: Hellboy Looks Hellishly Good in New Official Image