Precure stuff I've found online
To be updated very rarely.
/pc/ secret club
A massive MEGA folder with artbooks, coloring books, manga, some music and live shows, novels, and pretty much all the games.
Another MEGA folder. This one has the illustrations shown at the end of each episode up to Kirakira Precure a la Mode.
Inside the Media Mix: Collective Creation in Contemporary Manga and Anime
A dissertation by Bryan Hikari Hartzheim (whom the Brian in Smile! Precure gets his name from), a then PhD student who visited Toei Animation during the production of Smile. The paper includes a lot of inside info about Precure and Toei as a whole.
This site has an outstanding amount of production materials for Precure and other series.
Ultimate Precure Orchestra
A blog with downloads to most Precure music. None of it is lossless, but it's something (if you want lossless Precure music, pretty much all of it can be found on Nyaa, seeds willing).
Pretty Cure Wiki
The usual Fandom wiki. Good for trivia.
Lovely Warriors of Friendship
A site by an absolute weirdo -- tread with caution. I found it many years ago when I was looking for Precure models, and he still has the biggest collection in a single page, in MMD format, that I know of. The rest of the content is completely unhinged, but there are a few amusing things here and there.
Pretty Cure is property of Toei Animation. Please don't sue me.