BEST little know Jazz Album that you ever heard?

Not much of a jazz-hound but John McLaughlin's first album: Extrapolation. 

Charlie Haden "The Montreal Tapes with Don Cherry and Ed Blackwell" (one of several "Montreal Tapes" recordings).  It's essentially the Ornette Coleman quartet without, well..........Ornette Coleman!  They pull it off on a well-recorded piece that's worth exploring.

Frank Morgan "Mood Indigo".  Way, way WAY underrated and relatively little-known alto sax player who was something of a Charlie Parker protege'.

Woody Shaw "In My Own Sweet Way".  Another (underrated) trumpet player who was held in very high regard by none other than Miles Davis.

@tylermunns 

Thanks for the heads up. I will check the show out.

Only some of my list I would consider avant-garde. Maybe "progressive" would be the best description for most of my list.

I got to say, though, I am constantly surprised on how few jazz fans that post on music forums, are into exploring new stuff. So many great, creative subgenres. So many musicians with chops as good as the masters from the past.

An artist not unheard of, but not that widely known either, is Jimmy Guiffre. Sax, clarinet, composer, arranger, bandleader. Start with his "1961" album by the Jimmy Guiffre 3, comprised of Guiffre, Paul Bley (piano), and Steve Swallow (bass). A two cd album with most tunes written by Guiffre, but Carla Bley composed some of the tunes.  Recording sounds great.

The threshold issue here is: "What do you mean by 'jazz' "?  Ellington, Mahavishnu, Wynton, Alice Coltrane, Keith Jarrett, Sun Ra, Sinatra?  And are you including boots?

But here's my two bits: In the 1970s & 1980s, I collected a lot of mind-bending "Rock in Opposition" music that combined jazz, classical chamber music, electronics, and sometimes even heavy metal.  Lots of Chick, Zappa, even Yes influences. I also traded Western CDs, with penpals in the Soviet Union and Eastern Europe, for some more conventional jazz records by world-class artists who are little-known here.

I can make a few recommendations.  A good first stop would be Komeda's "Astigmatic," which -- and this is admittedly a poor analogy -- is something like Eastern Europe's "Bitches Brew."  Tomasz Stanko is no Miles, but still great.  It's on Tidal, & you Google Komeda for context.  Like Miles, he used to collect young talented players and guide them to become great bandleaders in their own right (when he wasn't recording soundtracks for movies like "Rosemary's Baby").

A good place to start for the RiO releases is with the bands Art Zoyd, Univers Zero, and Zao (the French band with Yochk'o Seffer & album "Z=7L"  -- there are a lot of Zao's).  Their albums are extraordinarily diverse and often experimental, but you may hear echoes of Weather Report & Pere Ubu.  Again, you can find a smattering of these artists' huge catalogs on Tidal.   Another option is Cuneiform's glorious sampler album "Enneade", which is also on Tidal (Youchk'o's "Freya" track is pretty hot!)

This is a whole world of jazz that is generally unknown to Americans and most younger Europeans.

Oh, and there are East Europeans who have released a only few albums here, but who have huge catalogs of great records that never made it to our shores.  YouTube is sometimes the best (mid-fi) way to sample such artists, like Michael Urbaniak and Iva Bittova (the "Polish Laurie Anderson"!).  I see a newly remastered version of Urbaniak's fusion-y "Inactin" is on Tidal.