I listen to podcasts all day at work so I've gone through a ton of them at this point!
All of them are spooky, horror or true crime, some fiction and some non-fiction.
Fiction: Welcome to Night Vale Alice Isn't Dead Small Town Horror The Magnus Archives Archive 81 Limetown The Black Tapes / Tanis / Rabbits The No Sleep Podcast Darkest Night Homecoming Creepy Podcast
Blended Fiction/Non-Fic (Curated "true" scary experiences off of reddit - that may or may not actually be true.) Lets Not Meet Scarecast
Non Fiction - True Crime/Unexplained Mysteries: Southern Fried True Crime Generation Why Sword and Scale Casefile Night Time Podcast Dark Topic
Journalism: Dr. Death Thunder Bay Serial S-Town The Shrink Next Door Escaping Nxivm Over My Dead Body Dirty John
I'm sure I'm forgetting some!!

I have been listening to Welcome to Nightvale again and holy moly? It's better than I remember. Really enjoying it.
I only listen to DND & other tabletop RPG podcasts haha Soooo The Adventure Zone Party Roll The Glass Cannon Those are my favorites :3
Currently binging The Anthropocene Reviewed, a very well written listen that will make you think :)
I keep making the mistake of turning on This Podcast Will Kill You while I cook/eat dinner.
I only listen to true crime podcasts. My favorite is True Crime Obsessed, but I also love a lot of the ones on Wondery.
Desperately seeking:
Morbid: A True Crime Podcast and H3 Podcast. I am fairly new to podcasts so so far I haven't dipped into very many
Stellar Firma: "a weekly Science Fiction, Comedy podcast following the misadventures of Stellar Firma Ltd.'s highest born but lowest achieving planetary designer Trexel Geistman and his bewildered clone assistant David 7." A hilarious podcast that recently returned for its second season.
The Magnus Archives: "a weekly horror fiction anthology podcast examining what lurks in the archives of the Magnus Institute, an organisation dedicated to researching the esoteric and the weird." An excellent horror podcast (I love it and I was never really a fan of horror before). My interest was initially sparked because I found out that the main character, Jonathan Sims, was canonically asexual.
Wolf 359: "Set on board the U.S.S. Hephaestus space station, the dysfunctional crew deals with daily life-or-death emergencies, while searching for signs of alien life and discovering there might be more to their mission than they thought."
I've only recently started on podcasts, but The Adventure Zone has been one of my favorite dnd-style podcasts.
I LOVE the Geologic Podcast, which is not about geology. Lol. The podcaster, George, is funny, down to earth, and talks to his audience like they’re right there in the room with him.
Also Talk Nerdy to Me, and The SGU. Oh! And Star-Talk!
I listen to a handful; I'd like to find more I like but I tend to lose interest fast if the hosts aren't very good (even if the subject matter is interesting!) I'm a big fan of Drag Race and drag shows in general so my favorite lately has been Racechaser (definitely recommend for other RPDR fans), Katya and Craig are good too. Other than that I've enjoyed S-Town and some episodes of Lore (though they tend to get depressing so I don't listen to it too often). I forgot all about Nightvale, that's one I'd like to try...
I'm kinda listening to a couple. I'm behind on some of them. butttt
Greetings Adventures (Drunks and Dragons) - A D&D real play podcast
Lore - Dark history tales; from mysterious creatures to weird places to tragic events
The Bella's Podcast - WWE (Diva's) Nikki and Bre Pella's podcast
Cabinet of Curiosities - Unbelieving, unsettling, and bizarre short tales
I love listening to the Cox 'n Crendor podcast while I work on crafts or when I'm eating lunch! They share the most hilarious stories and it really brightens up my day~
I wish I was more into narrative/fiction podcasts – I just don't have the attention span to listen consistently, so I end up missing things and getting mixed up or confused. (I'm much better with written media, I swear, haha.) I prefer non-fiction podcasts because I can tune out a little bit and look up anything I missed later, or if I miss something I don't get so frustrated at myself lol. I used to listen to Welcome to Night Vale, but I gave up once the continuity became too much for me.
My favourite podcast is probably Reply All, although they only upload every so often. Lots of great investigation work on weird Internet topics! I love that kind of stuff, being an Internet Old (well, kinda) myself. I also really like Oh No, Ross and Carrie! and This Podcast Will Kill You when I'm in the mood for feeling dread hahaha.
I also like true crime but I don't really listen to many podcasts because I don't like recorded 911 calls or anything like that – I just want to hear the story itself. I'm really picky with them - I only listen to some Last Podcast on the Left episodes because sometimes the goofing off goes on way too long and it's just like, lads, please, you must continue! I need recs for true crime 'casts that aren't too intense or too rambling, clearly.
I recommend Generation Why for true crime. The hosts have very calming voices, and they rarely go off topic. Some episodes do have recorded 911 calls, but only when the call itself is relevant to the case, i.e. Brandon Lawson, where there is significant debate over what is actually said on the recording. [edit]They do state in advance when they are going to play a recording so that you can skip over it or switch to a different episode.