I know that 5E is on its way out in favor of One D&D (can we please just stop with the dumb fucking buzzword names, WizBro? Just call it 5.5 or 6.) I guess that makes 5E retro, which will make me like it more, because I have terminal, inoperable stage 4 nostalgia. Rose colored cataracts are growing over my eyes.
Anyway, here's some stuff I wish had been revived during the 5E era:
Al-Qadim. I have a lot of the 2E stuff and could just, you know, run it that way, but I feel like AQ could use a fresh coat of paint. For one thing, maybe some playable races/species from Middle Eastern mythology, instead of "Yeah it's elves and dwarves but they're brown," which is how AQ rolled. Turn a couple of the kits into subclasses. The sh'ir could be an arcane tradition instead of a whole-ass class. Shoot, might not be a stretch to make it a flavor of warlock.
New Al-Qadim is very unlikely to happen, even in One D&D. No matter how they portray it, no matter how they re-imagine it, they will have a contingent of gaming discourse calling them racist and/or cultural appropriators, and they'll have some fucking beardos calling it woke SJW garbage if like, there's a gay in it or they don't have as much slavery as history did.
...but also, Al-Qadim isn't supposed to be the Middle East/Northern Africa, any more than Forgotten Realms or Greyhawk are supposed to be Europe. Anyway they handle it will be Bad and Wrong, and people will get mad on Twitter.
Oh, well. I guess I could always convert it myself. (hahahaha riiiiiight.) I think there was a person who did some kind of DM's Guild update, but I read some reviews last year and iirc it was pretty copypasta and not super useful/something I could do with the 2E materials I already have.
Planescape: I *think* this is actually happening, but I'm not sure. If it is, I'll happily shut my yap. Here's a setting where I'll stop bitching about tieflings. Honest.
Dark Sun: While there are some decent looking conversions to be found online, (I like this one, for instance) I would enjoy seeing some officially supported material. Slavery was a big thing in Dark Sun, so they will either leave it in and get yelled at, or take it out and get yelled at.
Dragonstar: This will never, ever happen, because it's from Fantasy Flight's 3.0 stuff, and Fantasy Flight got out of the OGL game a looong time ago. Hell, I don't even think Dragonstar got a 3.5 update.
Mythic Races: Again, this will probably never happen because it was part of Fantasy Flight's 3.0 "Legends and Lairs" material. I *loved* this book in undergrad. A lot of the races were so much more interesting than the furry-of-the-week approach that 5E got stuck in for awhile. There are a couple of humanoid animal races in there, but there were also some cool races that weren't just making an animal humanoid and sticking "folk" on the end. The ooloi, the luminous, the...I can't remember their names, but the yeti guys who basically ate magical PCP. Good shit.
I could probably grab the PDF and convert it myself. It's still available on DriveThru. I'm just not comfortable enough with the 5E mechanics right now to do much under-the-hood work. I also don't immediately need them for my upcoming Spelljammer game.
Star Frontiers: A late entry to this list. The inclusion of *literal Yazirian* in Spelljammer, with the Thri-Kreen and Plasmoids arguably standing in for Vrusk and Dralasites, I kind of wish that there had been some kind of one-off 5E version of Star Frontiers. It would also have the benefit of furthering the destruction of the shitbags at NuTSR. Imagine being such utter wastes of human skin that you have a commie lefty like me rooting for a multinational corporation to destroy a small publisher.
So, now that I've put off preparing my 5E game for a few more precious minutes, I will return to actual productive* activity. Carry on.
*as productive as preparing for a campaign really is.