Disclaimer: I don’t work for Forestry.io; I just happened to find it via search.
The Glitch starters have been super helpful with learning Eleventy! I’ve been trying out free (as in actually free, not just a free trial) headless CMS’s and really like Forestry.io. I found it very easy to connect to Github, set up the CMS, and upload images. (I like Netlify CMS too, but the config and Identity stuff requires more developer setup.)
It would be cool to be able to connect Glitch to Forestry to import an Eleventy site in the near future.