I was going to ask what else you like but you previously asked about Hellboy and there are Marcel and DC recommendations in there.

I'd definitely start with Mignola's Batman as they are Elseworld titles, so stand alone. If you want more Batman then try Grant Morrison's run or Scott Snyder's. With Superman, GM's All-Star Superman is a classic and is also standalone. Also DC need not all be about the spandex - I'm a fan of Alan Moore, Grant Morrison and the wider British Invasion of Comics, so you'll find great comics from them in the proto-Vertigo titles like Swamp Thing and Animal Man, which inspired the Vertigo imprint that gave use Hellblazer and Sandman (which I also mentioned previously), but also GM's Invisibles and Doom Patrol, which are definitely something else.

Over at Marvel, it's a bit trickier and, as has been suggested, try picking a character you like and dipping in. If we follow the horror angle, then Marvel have always done that well and I suggested Marvel Zombies previously and I'd give that a go. The early runs of Doctor Strange are great as it is peak Steve Ditko art. Beyond that X-Men are always a good suggestion - Claremont's original run is top notch and GM's New X-Men is great (even if it ended controversially). Alan Moore also had a fantastic run on Captain Britain that I recommend as it helped cement the building blocks of the Marvel multiverse. Given the character's popularity at the moment, you should check out Deadpool which is pretty solid once other writers got a go after Liefeld. I also think it'd be rude not to mention Warren Ellis' Nextwave, which is pretty self-contained and a real blast.

Which is a handy way to segue into recommending superheroes beyond The Big Two. There are a lot but Ellis' run on The Authority helped establish the "widescreen" format followed by a lot of modern comics. They are part if a wider Wildstorm Universe that can be explored (try Wildcats). There are plenty of other superhero comics - Jeff Lemire's Black Hammer at Dark Horse, for example.

Anyway, that's enough to get you started. See what takes your fancy and then you can get back to us and we can refine our suggestions.

When I owned a comic shop I would tell people start with the current issue, if it is part of a serial go back a few issues until you are at the start. Or find the most recent TPB.

I got back into Marvel comics because I got into the Marvel By The Month podcast. They read and review every Marvel comic, one month at a time, in chronological order, starting with Fantastic Four #1 in 1961. They talk about what was going on in the world at the time, get into the lives of the creators and the industry, and talk about how well they've aged (or didn't). Plus they've got an absolutely incredible murderers' row of guests. Matt Fraction, Tom Brevoort, Steve Englehart, Mark Waid, Brian Michael Bendis, etc etc. Learning more about the behind the scenes and the people involved reinvigorated my love of the art form.

You can get back into Superman with "The One Who Fell" trade.

I would start with a hero that you like. I dont think you have to pick either, just read what you like. So if you want to read Superman, just pick him up.

I did a little research on the best (standalone) stories of the heroes I wanted to follow, for example all star Superman, or Batman year 1. If I liked those, I would look at others, or recent editions.

Sometimes they branch out during runs, which would be reason for me to look at something new. For example there was a Black Panther series where he would have interactions with Xmen and Fantastic Four, causing me to read them and evaluate if I liked them.

Honestly it is all still quite overwhelming with how much stuff there is. Just pick something you like to get into it, and see it from there.

Lastly, this community is quite active and has some really good help, so if you pick it up again and are looking for nexts, come find us!