The Lord Weird Slough Feg is named after a comic book.

I came across a mention of "Iron Fist" superhero by Marvel (1974). I had never heard of that before:
https://en.wikipedia.org/wiki/Iron_Fist_%28comics%29
I don't see anything in Motörhead's song lyrics (1982) that would be an obvious reference though.

Some Judas Priest lyrics were inspired by Tom of Finland comics? OK, that's just a wild guess. Unseen Terror had several songs about Garfield.

Shadows Fall took their name from a comic of the same name.

Not at the start but Warhammer 40k comics have existed concurrently with Bolt Thrower's career, so that would still be inaccurate.

In an early version of Highway Star recorded on German TV in 1971, Ian Gillan as libs:

https://www.youtube.com/watch?v=AUtHC9L2CdI#t=66s
"like Steve McQueen, Mickey Mouse and all.."

Steve McQueen was among other things a car racer and his name is believed to have influenced the Disney character Lightning McQueen (cars) some 35 years later. Mickey Mouse is definitely a cartoon character.