First of all, where do u even find this music???
Well, it depends on a few factors and how ethical you want to be lol.
But before anything, I'd just advise to go around and just look yourself. I feel like the best way to discover doujin music (and really all music) is just by discovering it all by yourself.
Here are some databases you can use to browse and find some releases:
> https://www.discogs.com/
> https://vgmdb.net/db/events.php
> https://music.douban.com/tag/
> https://utaitedb.net/
> https://vocadb.net/
> https://touhoudb.com/
> https://en.touhouwiki.net/wiki/Doujin_music
Here are a few links to some general online shops/stores:
> https://www.diverse.direct/
> https://www.tanocstore.net/
> https://booth.pm/en
> https://bandcamp.com/
> https://www.suruga-ya.jp/kaitori/
If you want to buy anything second hand, your going to want to use a proxy service:
[I have found sometimes people will throw up some stuff on ebay or mercari over here in the US, but don't always count on it]
> https://buyee.jp/
> https://www.fromjapan.co.jp/en/
> https://aucfan.com/
Lastly, I included a link to VGMdb that showcases some doujin events. These events are a amazing way to discover new music and see what’s upcoming. The three main events I'd suggest to watch for are Comiket, M3, and Reitaisai (this one being specific to Touhou).
> https://www.m3net.jp/friend/
> https://www.comiket.co.jp
> https://reitaisai.com/
This is a highly condensed list of content and information... so if you have any suggestions or links, feel free to share them in this thread. Also, feel free to reply with music or anything related to doujin music!!!!!

