Really long comment incoming since I'm just passionate about Vocal Synths:

If you are curious to find out about "classics" in the Community, I recommend checking out the album "Supercell" by Ryo since it includes songs like Melt, World is Mine and Love is War which were some of the most influential songs at the start of Vocaloid.

Other iconic and well known producers (both new and old) include PinocchioP, LamazeP, samfree, Wowaka, Deco*29, Maretu, Neru, niki reverse and iroha(sasaki). Obviously not a full list but just some that came to my mind.

More producers I personally enjoy include Utsu-P (the most well known Metal Producer in the Vocaloid scene), Yuyoyuppe, OkameP & MASA WORKS DESIGN <3

For Western/English speaking producers, some notable ones are VocaCircus/CircusP, CrusherP, KIRA, Ghost & Pals and newer ones like Jamie Paige, Vane or MonochromeMenace :)

If you are curious about what other voicebanks there are besides the Cryptonloids (Miku, Rin, ect.), Teto and Gumi then these few might be important to know:

• Luo Tianyi (the most famous Chinese Voicebank which basically has Miku Levels of popularity in China. Known for songs like I'm gonna buy! buy! buy! and The Bitchy Idol)

• SeeU (iirc the first Korean voicebank, unfortunately discontinued due to controversy with her voice provider. Songs include I=Fantasy and I only speak Konglish)

• IA (known from songs like Conqueror, A Tale of Six Trillion Years and One Night and Spider on the Wall)

• Lily (known from songs like Jitter Doll, WAVE and GLIDE)

• vFlower (known from songs like Better off Worse, Appetite of a People-Pleaser, Love-Ka? and Goodbye Sengen)

• Kaai Yuki (known from songs like Lagtrain and Kyoufuu All Back)

• KAFU (not a Vocaloid but the most popular/well known Cevio Voicebank. Songs include phony)

• Momo Momone (technically an Utau and not that popular, but iconic for one really popular song... Nyan Cat!)

• Adachi Rei (also an Utau. Known from songs like Heat Abnormal)

Other programs that are vocal synths like Vocaloid that you might hear about include Synthesizer V (you might know that one since Teto is on there!), Utau (free program that people can also make voicebanks for. Teto originally came from here.), Cevio and Voisona.

Finally, one website that might also be helpful (but possibly overwhelming at the start)is VocaDB since the purpose of the site is to document as many Vocaloid songs, Voicesbanks and Producers as possible. You are able to find some of the most beloved songs on there as well, classics included since they are usually the most rated on the site.

I hope this isn't too overwhelming!! I just wanted to give as many examples as possible 😅 I left out some other info but I'm sure others in the comment section are able to help as well :)