commenting because i want to know too!
Is there a downloadable resource/library of clothes or kind of fashion with certain aesthetic, periods, and styles? So it can be used without internet...
I use pinterest to compile a bunch of outfits to put on OCs with but because the internet here in my place is a bit iffy. It's quite difficult to have no reference to use so i can have idea about how to put these ideas to the character.
Or maybe some kind of bulk or batch download a whole pinterest board and use them offline. Downloading each picture can be tiring, especially its 100+ of pics in the board
So I don't any specific resources, and this is definitely for more modern stuff, but it might be worth having a look at actual fashion magazines. You should be able to download PDFs through a lil' bit of googling. A quick search on archive.org for 'fashion magazine' comes up with a good amount of vintage 50's materials: https://archive.org/search?query=fashion+magazine (you might need to sign up to read them all fully but the site is free and works like a virtual library if I'm right)
https://freemagazinepdf.com/ has a whole bunch of magazines. 'Vogue' gave a good number of 2022 issues, if you can find out some magazine names then this could be a good spot.
As for Pinterest, a good alternative that doesn't rely on internet access could be PureRef. It's basically an image reference software that you can copy and paste images into or just drag them in, its got really easy organisation tools so you can line up and bunch together images, make them all the same height or width, and you can export the whole board too. Plus its great with drawing software because you can set it to 'always on top' so it'll just sit on top of your drawing app window.
If you're up for doing your own research about more historical fashion, then setting up a board for each style, period, aesthetic etc. could be really useful.
edit: forgot to mention this video!! its a basic workflow for moving images between Pinterest and PureRef, but you can also just copy and paste images without having to edit the URL for the originals if you want. There's a whole bunch more features that aren't mentioned in the video so I definitely recomend checking it out for references and moodboards in general