The following list is ideal for book cover designers and author branding that is evergreen and easy to use. You’ll find three sections of fonts that can meet various price points with Adobe Typekit (A) and Envato Elements (E) marked with links and icons that can be included with membership!
You can also check the following sites for sales on fonts, as well as featured bundles. Some links may include affiliate codes. Always double-check the licensing for each and make ure you have extended licenses. The following are known for their extended licenses in general:
Pixelo.net: https://www.pixelo.net/
The Hungry JPEG: https://thehungryjpeg.com/
Mighty Deals: https://www.mightydeals.com/
Design Cuts: https://www.designcuts.com/
Inky Deals: https://www.inkydeals.com/