The majority of Adobe's fonts are available on fonts.adobe.com as part of the Adobe Fonts subscription library. Perpetual desktop licenses, as well as extended licensing, are available from the following resellers:
You can still purchase Font Folio and Font Folio Education Essentials from adobe.com.
To learn more about Adobe Originals and the type design program at Adobe, you can visit the type section of Adobe.com.
You can find Source Sans, Source Code, and Source Serif for activation or web use from Adobe Fonts. You can also activate Source Han Sans from Adobe Fonts. The source files for all of these fonts are available on GitHub.