I was making a playlist for music for my Deadlands game and was curious if anyone did anything similar.

Either for writing or playing.

https://www.youtube.com/playlist?list=PLn7aprSeRhoXIoEY9MpjvpTRuQsv56bsv

I also use the Interview with a Vampire soundtrack for my Vampire games.

https://www.youtube.com/watch?v=TnW8mo-CksY&list=PLg8nvRjAWDhqooX_kijRYDvjeMbgPu_YG

For cyberpunk-themed games I like to use music from the new-retro-wave genre:
https://youtu.be/QpDn4-Na5co
https://youtu.be/8EGYVS7jUn8
https://youtu.be/BMOsLAz4II4
https://youtu.be/BP1C-W8A69s
https://youtu.be/wJpvegmziMg


And anything...

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https://youtu.be/aQGvlemqUpE
https://youtu.be/cU8HrO7XuiE
https://youtu.be/PrszgmYUldQ
https://youtu.be/F9L4q-0Pi4E

No music for us. Too distracting.

As mentioned in a similar thread recently, I only use atmospheric stuff that isn't recognizable.

This is my current go-to:

http://tabletopaudio.com/

It's incredible because each track is 10 mins long and loops perfectly. Also there's a soundboard that allows you to make your own sound effect loops with sudden cues if you want (a scream, gun shot, growl whatever).

Conversely, you can just download the 10 min tracks for offline use. Which I've done.

In the past, I've used a few different CDs/soundtracks for Call of Cthulhu gaming. Alex Otterlei's Dark Themes from Beyond (which I bought back in the 90s), Pelgrane Press' The Complete Eternal Lies Suite (though I don't play Trail of Cthulhu). Generally, just played them to add some ambiance to the game session.

But, these days I really don't have time for that. I've got enough going on as a Keeper, and there are other ways to set the mood that I find more effective.

I've done the music thing before, back in 3e. It was ambient sort of Midnight Syndicate stuff. I've done the sound effects thing too with .wav files. Didn't care for either one. And now that we had one player move from Texas to North Dakota and we Skype him in every Saturday, I think the music would interfere with the microphone anyway.

It varies by campaign.  Usually, I don't use any music.  But there have been notable exceptions.  In my Legion campaign I used a variety of songs from different decades to represent the era that was the equivalent period in comics history that the Legion campaign was going through.  In my Golden Age campaign I played some of the top hits from each year (1937-47) that the campaign was set in.  In my Wild West game, I've occasionally played some cowboy-themed country music to set tone at the start of a session.

In my Over the Edge campaign, I made use of "the Girl from Ipanema" as a repeated song to reflect the weirdness of the Island, and paralleled it with a sense of being trapped.

Film and video game soundtracks, but nothing well-known unless aiming for a specific effect. (Star Wars soundtracks only if we're playing Star Wars, for example.) You generally want stuff without lyrics. And you want stuff that suggest a mood without necessarily asserting it.

I used to create very specific soundtracks for scenarios (themes for specific NPCs, locations, etc.). But I've generally found this is more effort than it's worth, and managing the tracks during actual play is mostly too annoying. I'll be experimenting with this again later this year or early next, however, because I'll be running the Eternal Lies campaign a second time with a co-GM and having the co-GM manage the soundtrack in real time feels like it could work well.

What I mostly do now is create themed playlists for my iPod: I've got several different categories for my D&D campaign (City by Day, City by Night, Generic Dungeon, Banewarrens, Chaos Cults, Combat, Epic Combat etc.). I've also got lists for Cyberpunk, Horror, and Numenera.

None.
I've never seen it used well enough that I wouldn't prefer it just not be there at all.