Hi all, here are some that I've found useful lately or in general, plus short descriptions!
Google fonts (see individual licenses but generally free and okay to use in commercial products):
List of image resources, most of which from older media (which I incorrectly noted as being all public domain but actually vary):
https://www.moma.co.uk/public-domain-images/
Stock photos (see 'license' link on there for more info):
Mini typography guide (plus a whole book on typography that you can buy):
https://practicaltypography.com/typography-in-ten-minutes.html