Hania Rani: Esja.

Sleep by Max Richter is great (and very long)

Sunset Mission by Bohren & Der Club of Gore is very very sleepy Jazz (they have released more albums, but this one is my favorite by a wide margin)

Long Ambients 1 & 2 by Moby - he was kind enough to make them available for download free of charge, too

Under Wires and Search Lights by Marconi Union

In A Silent Way by Miles Davis

Pretty much anything by Sigur Rós. It's not strictly speaking instrumental, but the lyrics are Icelandic, which I don't speak, so it's close enough

Cocteau Twins recorded many very ambient-ish albums. Not instrumental, but the "lyrics" are mostly glossolalia, so not distracting (at least for me).

https://richardhoughten.bandcamp.com/music

https://domeniquedumont.bandcamp.com/

https://marylattimoreharpist.bandcamp.com/

https://archive.org/details/Tipper-CosmAmbientSet

https://williamtyler.bandcamp.com/

None of these artists are strictly ambient

A lot of great recs in this thread, but I'll a couple others I didn't see listed yet:

Mort Garson: Mother Earth's Plantasia

Hiroshi Yoshimura: Surround

Satoshi Ashikawa: Still Way (Wave Notation 2)

Shameless plug... Search BirdyMusic.com in Spotify/Apple Music/YouTube Music to hear some ambient music algo generated based on realtime Birdnet detections and weather in my backyard.

Drone Zone on SomaFM (free internet radio) was how I discovered a lot of that stuff. Although they don't play the old classics as much these days, it's still good and they have a few similar stations there https://somafm.com/player24/station/dronezone

Not OP but I also often to listen to ambient while programming. A couple recommendations would be "Music for Nine Post Cards" and other works by Hiroshi Yoshimura, and "Music for 18 musicians" and others by Steve Reich.

In fact, the use of loops described in this article reminded me of what Reich called "phases", basically the same concept of emerging/shifting melodic patterns between different samples.

For me - Aes Dana (Season 5 is still my favorite) and Carbon Based Lifeforms (Hydroponic Garden, World of Sleepers, Interloper).

Actually, check out the whole Ultimae catalogue: https://bandcamp.com/ultimae

music for programming podcast: https://musicforprogramming.net/latest/

some of the artists below are not strictly speaking ambient as in brian eno kind of ambient

jogging house, r beny, biosphere, anthony childs (surgeon doing ambient), abul mogard, alessandro cortini, alva noto (glitchy ambient), benoit piouliard, bing & ruth, bvdub, mu tate, jake muir, ulla, log et3rnal, space afrika, heurco s, donato dozzy - plays bee mask, imaginary softwoods, jo johnson, koen holtkamp, mountains, kyle bobby dunn, oneohtrix point never, neel, pendant, romeo poirier, domenique dumont, …

Woob 1194 by Woob. Immersive, maybe darker than most would like, but deep and very graphical sound.

https://woob.bandcamp.com/album/woob-1194

Biosphere - Shenzhou and Cirque, Stars of the Lid - The Tired Sounds of The Stars of the Lid are favorites of mine. I would also include everything by Microstoria which is not ambient but it works to the same end.

I have an 'Ambient Radio' channel on https://ambiph.one, my soundscape generator: https://ambiph.one/?m=1-Ambient+Radio-bf100

There are some great less-well-known artists on there - if you tap the album art it'll link you to their Bandcamp if they have one

A good place for experimental music is ubu web, in fact Brian Eno is also over there[1].

Edit:

Also if you're a programmer and what to learn a new programming language, then check out SuperCollider[2]. You can use that to create your own ambient sounds. SC has a great library for creating user interfaces along with creating sound.

[1]: https://ubu.com/film/eno_77_interview.html

[2]: https://supercollider.github.io/

If drone with later neoclassical touch then Marsen Jules has delivered very stable and top tier. Brilliant guy.

https://marsenjules.bandcamp.com/

For a good intro the Sleepbot Environmental Broadcast radio is well worth listening to. Also their write up on how and why they produce the broadcast is really interesting.

The best is the instrumentals on David Bowie's Low IMO.

I know people love Music for Airports but I think it is incredibly boring compared to what Eno did with Bowie.

Beyond that the first few albums by The Orb are top notch.

Balam Acab - See Birds and Wander/Wonder are incredible.

Here's a playlist list of long-form ambient drone stuff I've been curating for a couple years now:

https://youtube.com/playlist?list=PLGMYnukvmgiXXFxuTKDvZfw-e...

I listen to it while I work.

Absolutely! For instrumental focus music, check out Nils Frahm or Max Richter. Do you prefer more electronic or acoustic sounds?

i have a 5hr playlist on spotify called lost in the sea of ambien which happens to have many of the artist recos here. title is a reference to haruomi hosono who said he got lost in the sea of ambient in the 80s after leaving ymo.

Aphex Twin - Selected Ambient Works {85-92,Volume II}.

I have so many suggestions.

But if I had to pick one: Stars of the Lid - The Tired Sounds of Start of the Lid

Aphex Twin's "Digeridoo" is incredible. It's a 4-song EP so it repeats often, but that's a feature for me.

I've not seen Global Communication mentioned, 76:14 really is masterpiece. (Gamers will recognize a tune featured on GTA IV)

You might like Patrick O'Hearn.