Company Flow - Funcrusher Plus (1997)
Considered by many to be the greatest underground record of all time. Between El-P producing and emceeing with Bigg Jus, this album evades conventional hip-hop motifs, and instead focuses darker atmospheric sounds over electronic and deep bass-focused instrumentals. The low-fidelity sound is charming, as well.
https://www.youtube.com/watch?v=cn5Hx1DmDz8
Daedelus - A Gent Agent (2004)
This album is one of my personal favorites, since Daedelus produces fantastic, full sounds from obscure film, electronic, orchestral, and other sources. The whole album is somewhat reminiscent of DJ Shadow's Endtroducing for me, but it definitely has a different feel to it, since it's not particularly hip-hop based.
https://www.youtube.com/watch?v=DGGuTm3Dqy4
Dela - Translation Lost (2012)
I heard this album last year, and I thought it was just a decent album, but it definitely is promising. It's a project by some European producer who uses immersed productions with catchy rhythms. Each song has surely been stuck in my head at least once. The problem with the production is probably since it lacks so much atmosphere, which kinda lowers the potential for the album, since it seems like that was its intentions. It sorta reminds me of the Floral Shoppe album, except more focused on melodies rather than a repetitive drone of 80s ballads...
https://www.youtube.com/watch?v=WbXAx4fnY-E
Deltron 3030 - Deltron 3030 (2000)
With Del the Funky Homosapien on the mic and Dan the Automator on production, this album is fantastic. It has experimental topic discussion with esoteric futurist themes, as it's based in the year, as the title suggests, 3030. The production is very dynamic, with odd samples and sporadic orchestral and brass rhythms blasted from time to time.
https://www.youtube.com/watch?v=qX5A0SO8Yqw
Dr. Octagon - Dr. Octagonecologyst (2000)
This album is also produced by Dan the Automator, and has rapper Kool Keith from Ultramagnetic MCs under the alias of Dr. Octagon. The production on this album is much more darker and atmospheric, sort of like a mock horror film. You may or may not like it. Kool Keith doesn't try to impress the listener with his lyrical prowess, but it's still a great listen, since it's meant for entertainment rather than impressions. One of my favorite. I like it more than Deltron 3030.
https://www.youtube.com/watch?v=tjKHQeRSvjk
Edan - Beauty and the Beat (2005)
Edan displays both production and lyrical skills on this album. The beats primarily sample psychedelic rock, which results in a dope sound that sounds produce mesmerizing and aesthetic imagery. This album is probably in my top ten favorite hip-hop albums of all time.
https://www.youtube.com/watch?v=8DK8TkP0DzM
El-P - Fantastic Damage (2002)
After collaborations with artists like Company Flow and Cannibal Ox, El-P released his debut solo album. The album is dark, but more melodic and energetic sounds than those shown on Funcrusher Plus. Also, El-P is a great lyricist on this album, as well.
https://www.youtube.com/watch?v=zQUm8EZLjoo
King Geedorah - Take Me To Your Leader (2003)
This album is an alias of rapper MF DOOM. I really like how the production isn't held back at all; the highs are high, crispy, and smooth, while the lows are deep and full. It's not conventional producing and varies from track to track, which fits with the many featured guests on each track. This album was also released the same year as Vaudeville Villain, which seems to make a dichotomy, at least in my mind, since the album covers are black/white and DOOM raps on all the tracks on Vaudeville Villain and produces none, while on Take Me To Your Leader, he has many features and produces each track. It's a great listen.
https://www.youtube.com/watch?v=leDzWauY5Tw
Madvillain - Madvillainy (2004)
Madlib has wonderful productions striving from odd samples beside MF DOOM, who drops great verses each track. The songs last 1-2 minutes each for the most part. It's sort of like reading an engaging comic book. Definitely in my top ten favorite hip-hop albums of all time.
https://www.youtube.com/watch?v=weWTuvdL-LQ
Quasimoto - The Unseen (2005)
https://www.youtube.com/watch?v=iEHRz_4ROLQ
Got lazy after a while, as you can see. Tired.
I'd say listen to them in this order:
Madvillainy, Deltron 3030, Funcrusher Plus, Beauty and the Beat, Fantastic Damage, Dr. Octagonecologyst, The Unseen, Take Me To Your Leader, Translation Lost