If you're even vaguely familiar with visual novels released in the past twenty years, you've most likely encountered the incredible music of Takeshi Abo at one time or another. With over 230 composer credits to his name in the Video Game Music Database, to say he's prolific would be putting it mildly — and that's not including credits for games that never received soundtrack releases (such as RHYME☆STAR, released in 1994 for PC98).
Abo is most well known for his visual novel music, including KID's Memories Off series, KID's Infinity series (Never 7, Ever 17, Remember 11), and 5pb.'s Science Adventure series (Steins;Gate, Robotics;Notes, Chaos;Child). Outside of that realm, he also handled the music for the arcade-style beat 'em up Phantom Breaker and Phantom Breaker Battle Grounds. There are many more works I have neither the time nor space to mention here, but I highly recommend exploring as much of his music as you can. Thankfully, accessing at least a small part of his immense catalog has become easier thanks to several of his soundtracks being published in Hi-Res digital formats. There are several sites that carry these releases, but currently Mora and OTOTOY have the largest selection.
Many of the more well-known soundtracks from the series mentioned above are available. However, there are also several deep cuts, including soundtracks that never received retail releases and were once only available as special bonuses to limited edition or first-press versions of the games themselves. This latter category includes Liberation Maiden SIN and Hanasaku Manimani. I was also very happy to see Separate Hearts ~Original Audio Collection~ in the list, which is in my top 5 Takeshi Abo soundtracks. While it did have a physical release in 2006, the CD has become extremely difficult to find, so I'm thrilled that more people will have the opportunity to discover it now.
I will always prefer owning a physical copy of a soundtrack if one is available, but as the older or more obscure titles become increasingly hard to find, it's great to know that at least some music is being made available digitally. I can only hope that even more of Takeshi Abo's wonderful music makes it to these online storefronts, and that other companies and composers take note and follow suit with their own catalog of soundtracks.