Here is, I think, an interesting and recent addition to the types of history syllabi available online: not just those for college classes, but ones created by and shared among community (I often see them in anti-racism contexts for example). As an example --

https://www.americangirlspod.com/addy-add-on-the-syllabus

Public historians Allison Horrocks and Mary Mahoney organized a crowd sourced syllabus to provide greater historical context to the Addy books in the American Girl series. This project came about as a result of their podcast which provides entertaining commentary and historical context to the AG books, and around which they've created a history minded community.

This community-built and community-referenced syllabus, easily accessible on Google Docs, seems to add a new dimension to history syllabi available/created online.

This reminds me of the messiness of public/digital history taking place on social media. Earlier commentators on this thread were speaking about the possibility of a third wave of digital history, or if the stated goals of this second wave have been achieved -- I think in some ways we can see this hoped for expansiveness in the current way people use history online.