From anosou.music:

Quite a few games never got a soundtrack release but have been brought
to the mighty internet in form of game rips, either from the ROM or
direct audio recordings. Here I’m gonna mention a few that’s worth
looking into. From Software’s extremely overlooked Lost Kingdoms II (known as Rune II in Japan) has some quirky music.

From Software head composer Kota Hoshino is joined by From Software regular Yuji Kanda and Takeshi Yanagawa
of Culdcept fame for the soundtrack, never released in stores, and it
certainly has it’s moments. A strange blend of ethnic, electronica and
classic RPG music that makes up for the lack of sample quality with
unique compositions. Highlights include Battle, Gromtull Desert and Kendarie Fortress. A must if you’ve played the game.

Whoopee Camp’s PS1 cult hit Ore! Tomba also has
some fantastic music. Happy-go-lucky music based mainly around
mallet-type sounds and percussion with really strong melodies. This
soundtrack went great with the crazy art style of Ore! Tomba, the
pink-haired little boy battling against evil pigs, solving mysteries
and helping people. Highlights include Dwarf Forest, Village of all Beginnings and Phoenix Mountain. Harumi Fujita
(Pulstar, Blazing Star) and Nao Hatsutani really made a memorable
soundtrack and it’s a shame it goes unreleased. Since Ore! Tombe (or
Tomba! or Tombi! as it’s also known) is such a rare game many people
will miss out on this so hunt down that game rip NOW!

Future Tactics: the Uprising might have been a bad game, I don’t know, but goddamn the music is groovy. Tim Follin,
one of the best NES/SNES composers out there, finally got his hands on
some real samples and made some fantastic tunes. The soundtrack is a
groovy, funk-inspired blend of jazz flute infested jam sessions,
extremely atmospheric semi-ambient pieces, folkmusic and
balls-to-the-wall rock. The instruments sound authentic, the riffs are
strong and Follin really showed why he was one of the greats (he’s now
retired from game music). Find it, enjoy it and beg to a god of your
choice that Tim Follin gets back into game music.

Long story short, there’s a LOT of good VGM out there that never got
a soundtrack release. That doesn’t mean all hope is lost, game rips is
fan effort at it’s best and will give you hours of listening pleasure.
It’s probably not legal in SOME way but damnit, I fail to see anyhting
wrong with it if the game never got a soundtrack release. Anyway, if
you have any personal favorites be sure to let me know and I’ll check
them out.