[Closed] What other albums as complete and great as Dark Side of the Moon?

Soundgarden - Superunknown
Van Morrison - Astral Weeks
Screaming Trees - Dust
Kyuss - Welcome to Sky Valley
James Brown - In The Jungle Groove
CCR - Willie and the Poor Boys
Highly Suspect - Mr Asylum
Frazey Ford - September Fields
Bob Dylan - Blood on the Tracks
Neil Young - After the Goldrush
Deltron 3030 - Deltron 3030
Arcade Fire - Funeral

as I have not heard of most of the non mainstream bands mentioned

Not really. All threads like this quickly degenerate into a "name an obscure band ****athon".
Greatest album of all time - Sgt Peppers? Naah man, it was Fondle My Goolies by The Throbbing Teakettles.
🙂

Mine are pretty obvious!

Forever Changes. Love. Surprised no one seems to have mentioned it.
Revolver. The Beatles
Up to Our Hips. The Charlatans. Probably their most 'complete album' album.
Fifth Dimension. The Byrd's
Sea Change. Beck
Takes a Nation of Millions to Hold Us Back. Public Enemy.
Howl. BRMC
Rubber Factory. The Black Keys
Three EP's. The Beta Band
To The Death of Fun. Cashier No. 9
Zooropa. U2. I think it is more thematically complete than Achtung Baby.
Blood on The Tracks. Bob Dylan

Good shouts already for:
Laser Guided Melodies
Dog Man Star
Screamadelica
Otis Blue
Southern Harmony & Musical Companion
What's Going On

Edric 64 - Member

Must be getting old as I have not heard of most of the non mainstream bands mentioned

I think the youts won't recognise most of them tbh, nobody on STW's discovered a new band for a decade except via radio 6 or TV adverts.

Joe's Garage.