Seconding ASIP. They curate an ambient radio station in collaboration with a bunch of other ambient labels, and it’s an excellent choice to avoid the significant stress of trying to pick an album
NTS also have some excellent ambient shows. ‘Sounds of the Dawn’ is one of my faves, tho it’s heavily new age so not to everyone’s tastes. They also have 24/7 mixes (the ‘infinite mixtapes’ tab on their site) and Slow Focus is a collation of various of their ambient shows
I’m currently in love with the label Astral Industries’ catalog
https://astralindustries.bandcamp.com/
Biosphere does excellent stuff
Oneohtrix Point Never’s R Plus Seven is astounding, though it might be a bit too engaged to properly count as ambient
Ambient made on guitar - that doesn’t sound like guitar, from my own musical partner for the past two decades, Har:
Pretty much anything from Steve Roach does it for me, from his slow, deep ambient stuff to his modular sequencery. I love the guy:
Classic space music from Kevin Braheny:
Another cosmic classic, this one from Michael Stearns:
I remember being blown away the first time I heard disintegration loops
On the darker side…
Ali Khan/Yoyu from here in Winnipeg has some lovely, lovely pieces:
Just a wonderful human too 
Thats some choice recommendations. Nice ! Try this out too : https://soundcloud.com/roelfuncken/sets/ambient-sets
Another thumbs up for Astral Industries label.
Can’t get enough of their aesthetic.
The latest highlight from them is Multicast Dynamics - ‘Ancient Circuits’, one of the most magnificent things I listened to all year.
10 years ago I kind of rediscovered ambient (and related) stuff, and was sufficiently inspired by all the wonderful stuff I was hearing that I started putting together mixes as a way to share my inspirations and hopefully put folks in touch with artists they might not have otherwise heard of.
Here’s the last one I did:
Alternatively, just take a look at the tracklists from the various mixes and follow up!
Standout artists I keep coming back to:
Stars of The Lid
Loscil
Deaf Center
and latterly, Jogging House
Unlikely gems I discovered along the way:
Arve Henriksen - Cartography
Alex Zhang Hungtai - Divine Weight
Youtube has been feeding me loads of old Japanese ambient lately, here’s three good channels
I also like the new version with drums. Not sure how ambient this is, but the melody is stuck in my head.
Here’s a few of my favorites:
A couple that are really special to me are “make me know you sweet” by pendant
And “$uccessor” by dedekind cut
Which I’m sure some wouldn’t consider ambient but definitely one of my favorite albums all time
Absolutely love this!
Here’s my guy… never puts a foot wrong. Any questions are always answered so kindly too.
That Buchla is simply awe inspiring too.
Look forward to listening to these recommendations, I’ve been getting more and more into ambient over the last couple of years.
One of my favourite artists is Bee Mask, his albums “Elegy for Beach Friday” and “When We Were Eating Unripe Pears” are very good, as is Donato Dozzy’s take on his “Vapourware” album. This track is the one that brought him to my attention:
Klaus Schulze
If the orb uf orb is considered ambient( probably not) that would be my favourite
Pete Namlook, i like his -oh, ifell asleep on my keyboard- albums, but more i love his trance stuff as 4 voice
Dimmat.
well, i know it’s a psy chill and this is cheating, but in 2020 „ambient“ is an umbrella term for a bunch of subgenres anyway.