Birthday edition!
Previous thread >>4413955
*List of archived threads:
https://pastebin.com/TXKE0xAT

*The Ricchan archive, contains DL links for the K-ON! Illustration archives, the けいおん! Live Concerts, Sato Satomi's discography, Ritsu's Image songs in FLAC, and the official Keion desktop app (calendar widget, desktop mascots, system sounds changer, clock widget, cursor changer and a wallpaper manager):
https://mega.nz/#F!WsBWhATa!pkf8TUBIsdChuh02DZ0_qA

*Anon's vector project:
https://mega.nz/#F!IoZR1S5K!PURHPUos2YtdOxIGRJaoiw

*きららファンタジア Illustrations, K-ON! Movie Creator Message book scans and Movie Setting Booklet (scanned and uploaded by anon)
https://mega.nz/folder/4cMWhLCJ#tH5vawpafAQxSYg6QjqmXg
https://mega.nz/folder/wZUnkawQ#U0iZsn11gA3L6UhPEVYHKQ
https://mega.nz/folder/VUtD3YqB#YO3s1i9PijaBGhQviZQBPg

*Need help finding sauce on a particular image?
Try these, which can lead you to even more Ritsu:

>yandex (can find source even if the sample image is cropped)
https://yandex.com/images/

>saucenao (links to boorus as well as the pixiv ID if any)
https://saucenao.com/index.php

*Need help organizing your collection of Ritsu?
>https://hydrusnetwork.github.io/hydrus/