the whole "Concept Album" term is rather ambiguous; you could say most albums in general are "concept." I guess when referring to "Rock Operas" it's a bit more specific.
I agree with the original poster about The Who's "Quadrophenia" it's a "Rock Opera" and later made into a movie which had Sting make a cameo. Both the movie, and especially the album I find to be highly superior to the one they're much more well-known for in "Tommy."
But as far as "Concept Albums"..I guess I'd just look at a large percentage of my favorite albums of all-time.
https://rateyourmusic.com/list/SoundscapeMN/the_100__and_beyond__Marillion - Brave
Kevin Gilbert - The Shaming of the True (this is maybe the most *important* concept or other album to me, in it's many messages about the music industry).
Soundscape - Discovery
Pain of Salvation - The Perfect Element I
Jethro Tull - Thick as a Brick
Queen - A Night at the Opera
Fates Warning - A Pleasant Shade of Gray
King's X - Gretchen Goes to Nebraska
dredg - El Cielo
The Receiving End of Sirens - Between the Heart and the Synapse
Angra - Holy Land
Coheed and Cambria - Good Apollo I'm Burning Star IV: Volume One: From Fear Through the Eyes of Madness
Pink Floyd - Animals
Kaddisfly - Set Sail the Prairie
Apes and Androids - Blood Moon
The Dear Hunter - Act II: The Meaning of and All Things Regarding Ms.Leading
Return to Forever - Romantic Warrior
Between the Buried and Me - Colors