The Monster of Frankenstein (1973)
We've already talked about how the Monster's first appearance in the Marvel Universe wasn't really him at all thanks to the Comics Code. But in 1971, Marvel published an issue of Amazing Spider-Man that - at the request of the US Department of Health - dealt with the dangers of drug use. That was against the Code and the Comics Code Authority refused to approve it, but Marvel chose to publish it anyway without Code approval. And the Code flinched.
That same year, the Code relaxed its standards and by October Marvel had introduced Morbius the Living Vampire into Amazing Spider-Man. That was followed by the first appearance of Werewolf by Night and Tomb of Dracula the following year, and the real version of Frankenstein's Monster debuted the year after that.
The history of Marvel's Monster of Frankenstein (eventually re-titled The Frankenstein Monster) is a long one and you should read Panelology's excellent article about it if you're interested in knowing more. It began with a faithful adaptation of Shelley's story, but with a different framing sequence in which a nineteenth century descendant of the novel's Sir Robert Walton rediscovers the Monster frozen in ice near the Arctic Circle. From there, the Monster goes into the world to seek out the last descendant of Frankenstein. Meanwhile, modern day adventures of the Monster also appeared in Marvel's black-and-white magazine, Monsters Unleashed.
Artist Mike Ploog created the look for Marvel's Monster, using Son of Frankenstein's fur vest, but little else from the Universal version. In fact, Ploog's Monster was the most faithful one to date with it's pale complexion, gaunt face, and long, black hair.
Flesh for Frankenstein (1973)
Originally known as Andy Warhol's Frankenstein (Warhol produced it), Flesh for Frankenstein is a spoof, but an extremely odd one. I've not seen it, but my understanding is that it's more interested in poking fun at sexual repression than horror tropes. In the film, that repression is apparently released in graphically violent ways, resulting in a mixture of sex and violence that's as horrific as any film writer/director Paul Morrissey is parodying.
The plot has to do with Frankenstein's attempt to build a perfect race and he gets closer than any screen Frankenstein before him. His creations, one male and one female, are beautiful except for a few stitch marks. Instead of going homicidal because people are afraid of his ugliness, Flesh's Monster kills out of rebellion against the horror of his megalomaniacal master. It's an interesting twist because it highlights that the Monster's problem (in all of his iterations) has never been about his appearance, but about the selfishness of his creator.
Frankenstein: The True Story (1973)
Warhol's version wasn't the last time the Monster would be portrayed as beautiful. In fact, later that same year, NBC ran this two-part mini-series in which the Monster came out looking great at first, but decayed as the story progressed (the image above is from an in-between phase). In spite of its title, it's no more faithful to Shelley than any other version. In addition to the Monster's degeneration (which I suppose was to make it more heart-breaking when he's ultimately rejected by Frankenstein and society after initially being praised by them), there are strong elements from Bride of Frankenstein (a Dr. Praetorius-like character; Elizabeth survives her wedding night) and several of the Hammer films (controlling the Monster with hypnosis; the Monster's Bride getting her own character arc).
But standing as its own thing, it gets a great review from Frankensteinia and features an excellent cast including Leonard Whiting (Zeffirelli’s Romeo) as Victor Frankenstein, James Mason as Dr. Polidori, David McCallum as Clerval, and Jane Seymour as the Bride. There are even small parts for Agnes Moorhead (Victor's landlady), John Gielgud (the chief constable of the police), and Tom Baker (a sea captain who's connected to Frankenstein's being in the Arctic, but isn't Walton).