My latest area of investigation. Found some really great stuff so far. Give Mother Desert a try.

https://motherdesert.bandcamp.com/music

Perhaps The Blue Sunshine Family Band

https://bluesunshinefamilyband.bandcamp.com/album/the-blue-sunshine-family-band

Ambient trance music sometimes has a rock sound.
Bjorn Lynne does a lot of music for games.
Tho some of his music does have singing/words most of it is instrumental.

There's also a wealth of Midi compositions available which have no words and can be very psychedelic.

I've listened to some rock music from India (on Shoutcast world radio) which has vocalizations but no lyrics. A type of scat singing which merges with flutes. Very soothing.

I listened to Mother Desert - Spirit (Full Album)
http://www.youtube.com/watch?v=lMB0VqKlm-Q
I like it, thanx for the recommend

The Blue Sunshine Family Band (Full Album)
http://www.youtube.com/watch?v=xNBeqarsHnk


Here's Green Orbit - First Wave (Full Album)
http://www.youtube.com/watch?v=bRkf-Z68mmY

Breaking Dawn Of The Blue Nebula "ΔS" (Full Album)
http://www.youtube.com/watch?v=GjGXjepZxAc

Hey Tom. Just settling in to give your recommendations a listen . Have a fantastic day.

i found these guys a few years ago


https://www.youtube.com/watch?v=7_H_rWs4RhQ

gotta get Shpongled...

https://www.youtube.com/watch?v=sgkDmycSGdE&list=OLAK5uy_lO3TfG9QCKWs6UgcsDq_2HytuX7v1FFBg

The Doors