The cartoons are right out- none of them bear much resemblance to Howard's character other than the name. Same goes for the live action series.
Pigeons is kind of an interesting one- you can watch it on YouTube. Boris Karloff hosts it and it starts out with the titular pigeons. The story tracks pretty close to the source, complete with very hatchet murders and swamp voodoo. The alterations are relatively minor (Griswell becomes Branner's brother Tim, for example). I would categorize this as a faithful adaptation to a story that has some racial facets that haven't aged well.
The 1980's Conan movies are a mixed bag. I think it is not a stretch to say that the first is considerably better than the sequel. It's a fun movie with some great imagery, lines, and music. However, the Conan portrayed is pretty loosely linked to Howard's Conan and nods a lot to the Carter and de Camp pastiches as well as the comics. It's a pastiche of pastiches. Cheesy and overdone (but fun) while Destroyer was pretty bad (though not terrible as a standalone fantasy movie). This Conan is not a very accurate adaptation. It also established the big, dumb barbarian standard.
Red Sonja doesn't even get close to Howard's Sonya of Rogatino. Definitely more comic inspired and the cameo not-Conan was weird.
Kull the Conqueror- So we have an attempt Hour of the Dragon with Kull instead of Conan. I say attempt because the movie is a mess. The plot is inane, acting terrible and I couldn't help but feeling it was a bad Hercules the Legendary Journeys episode. In reality, it was just the abandoned script that was supposed to come after Destroyer. Nobody who worked on it seems to like it. A stinker that doesn't get close to the more cerebral Kull or the instinctive Conan.
Solomon Kane continues the tragic pattern of trying to rewrite Howard's characters for screen. The movie is a CGI action flick with none of the moral conflict of the literary character. It doesn't bother with the historical grounding of the character, either, placing a Catholic monastery in Elizabethan England because reasons, not to mention being unable to comprehend that Puritans were not Quakers/pacifist. It also tacks on a bunch of nonsensical backstory to Kane. Another miss.
I could not have a picked someone better suited to look the part of an impressive Conan than Jason Momoa. Too bad he was shoved into a forgettable, murky mess of a movie. It's almost as if the writers skimmed the back covers of some Conan books and figured that was close enough. It is baffling that they spent so much front end on Conan's (newly minted) birth and childhood but spent absolutely zero time developing the core dynamics of the Conan (civilization vs. savagery, power vs. integrity, etc.). Another miss as an adaptation and another not good movie.
So, all in all, a pretty poor track record. A 1960s tv show came closest to the original, and none of his major characters seem to get a good shake. Which is odd as Howard was a pulp writer aiming his works at audiences to make money. He was writing at a time when technology and societal change was causing uncertainty and turmoil. Traditional institutions seemed to be faltering in offering answers. Global conflicts and warfare had left scars on a nation that often seemed to be regionally and culturally divided against itself. People flocked to entertainment as both distraction and catharsis. Any of this sound familiar?
His themes draw heavily from both history and mythology, but adds a visceral directness that avoids getting too overtly intellectual. So you get action stories looking at bigger questions about man's nature and place in the world.
digs into his stash of discounted collectible pre-paints.
