Check out these links to accordion sheet music sites and video tutorials! Thank you internet people, you're all too kind.
818 Accordion Music – This site has categorized so many accordion songs from musette all the way to latino.
Maestro Don Quattrocchi – A rather vast collection of sheet music arrangements by Don, a retired music teacher from Australia. All in PDF format with some accompanying YouTube videos.
Play and Teach – Has a lot of content on how to play a lot of accordion "classics" on YouTube.
Mosche Zuchter – Also teaches the piano accordion, his video tutorials focus a bit more on music from our generation like Beirut! He's got a Patreon and takes requests.
Eric Bouvelle – A professional accordion player from France who provides free sheet music in a variety of styles available in PDF format and mp3.
Gold Accordion – Not just a Russian accordion site but THE Russian accordion site. Plus points if you can ready Cyrillic but if you can't, fire up your Google Translate or click on the fifth link "Нотный архив" in their menu.
Balkanarama Sheet Music – Fancy some Balkan tunes? All transcribed by Mike Gordon, comes in gif format.
Boxes without Borders – A tumblr blog full of sheet music from all over and a recording of each. May be a bit difficult to navigate though.
Jan Wolters Sheet Music – Songs ranging from national anthems to children's and folk songs in Europe. Not all of these are for the accordion though, so you'll have to search a bit.
MuseScore – Technically a free program for users to write sheet music but a lot of people contribute and upload their work.
