List of songs just to make a list of illustrators to expand their song entries later.
What I use to find unknown creators of artwork:
* Greenshot - a tool to capture screenshots of any size with Print Screen key. It also provides way to easy edit images for presentation purposes,
* SauceNAO - the greatest reverse image search. ~~I should donate the creator.~~ Indexes pixiv, Nico Nico Seiga, imageboards and recently deviantArt. No piapro so far,
* Wayback Machine - as it says, web archive. Used for artists with deleted acounts just to make sure the used artwork is theirs.
Number of works is based on messages announcing use of artist's work on piapro (使われました section). These derived works may be unrelated with voice synthesizers.