[!!This list will likely be reorganized/downsized over time]
Nanosounds is a doujin record label comprised of various video game music composers, primarily from Namco. Sweep Records/Supersweep is a publisher and sound studio of similar origin. They frequently collaborate to produce NanoSweep.
Many of the artists between these two groups have a distinct sound. Unfortunately a compilation of every relevant game and artist here would be incredibly unwieldly, so I've only included composers from each group who appear on NanoSweep albums.

Featured Composers※:
Nanosounds: Hiroshi Okubo (Founder), Tatsukazu "Nakany" Nakanishi, Nobuyoshi "Sanodg" Sano, Akitaka "AJURIKA" Tohyama, Ryo Watanabe

Sweep Records: Shinji "MEGA" Hosoe (Founder), Takahiro Eguchi, Jun Kadoma, Atsushi Ohara, Ayako "AYA" Saso, Masashi Yano, Yousuke "YOU" Yasui

※In most of these games, the relevant composers here are given partial credit for the soundtrack. In some cases I have listed the individual tracks they worked on. Please consult VGMdb to find more specific information on the composers behind each game.
※※ Games/franchises withheld for brevity/cohesion: Alice Gear Aegis, Arcaea, Beatmania IIDX, Chunithm, DJMAX RESPECT, God Eater, Groove Coaster, Final Fantasy, Maimai, O.N.G.E.K.I, Pop'n Music, SoulCalibur, Superbeat XONiC, Taiko no Tatsujin, The Idolm@ster, We Ski, some obscure games not on IGDB

Other relevant artists to check out:
Nanosounds: Satoru Kosaki, Yuu Miyake, Keiichi Okabe, Asuka Sakai
Supersweep: Kazuhiro Kobayashi (former), Manami Komatsu, Kaoru Ohkoshi (former), Shoichiro Sakamoto (former), Teruo Taniguchi, Yasuhisa Watanabe (former), Takahiro Yagi