The starting point of the entire franchise is the five volume manga simply titled Devilman from 1972 written by Go Nagai. At the time I write this its 51 years old! The art style is goofy at times but its charming!
The plot goes as follows; the protagonist Akira Fudo and his best friend Ryo Asuka find the fate of the world in their hands. Akira absorbs the powers of the demon Amon thus becoming a creature called "Devilman".
Only a month later in July 1972 was the anime television series also titled "Devilman" that really has nothing to do with the manga. Akira appears for (I believe) two minutes in the beginning of the first episode before being killed off (in a hilariously tragic manner) and Ryo doesnt appear at all.
Akiras dead body is possessed by the demon Amon who falls in love with Miki Makimura and betraying the demons. Every episode follows a monster of the week format. I would highly recommend for some campy fun, it rules! (Also Miki and Amon's relationship is endearing as heck)
Next is what the franchise is most well-known for; the OVA series (original video animation) and their glorious dubs. First is Devilman: The Birth from 1987, an adaptation of the first volume of the manga.
In 1990, the second (and last) OVA was released, Devilman: The Demon Bird adapting the second volume and some of the third volume. The OVA series was then canceled due to Japans economic bubble bursting around the time.
The team for the OVA series went on to work on a three-part OVA series in 1991 (spanning February 21 to June 27) titled "CB Chara Go Nagai World", a chibi parody crossover of Go Nagais works Devilman and Mazinger Z (with appearances from his other works Cutie Honey and Violence Jack).
In 1997 was the "sequel" to the original Devilman manga, Devilman Lady. Devilman Lady is bad. I do not like it. Nobody likes it. Do not read it.
There is also a 1998 anime that loosely adapts the manga, loosely as in it takes the 1972 Devilman anime route of not following the manga at all but without any of the 1972 animes charm.
In 1999, there was the three volume manga run of "Neo Devilman", a compilation of various short stories by different mangakas. My personal favorite has to be the fifth story.
Amon: The Apocalypse of Devilman is an OVA released in 2000 and is sometimes confused as the "ending" of the original OVA series. It is not. I believe its an adaptation of the Darkside Manga but I have not read it so Ive got no clue.
Gekiman is an autobiographical manga by Go Nagai that ran from May 21, 2010 to September 7, 2012 about his time working on the original "Devilman". Here are some highlights.
In 2015, there was the three-part OVA crossover between Devilman and another old manga, Cyborg 009 (first published in 1964). Its rather Cyborg 009-focused but it has some of my favorite characterizations of Ryo and Miki in the brief moments they do appear.
The OP and ED slap though, go watch it!
In 2018, Devilman Crybaby was released. Its a modern adaptation of the original story. I only skimmed the last few episodes. I usually forget Crybaby exists!
If anyone is interested in watching/consuming anything listed here or in this franchise in general, please google the trigger warnings. Its something I myself shouldve done.