It's not released yet, but I've got the code working to have @backup_brain connect to your Mastodon account via oAuth and ingest and archive all your bookmarked posts on an ongoing basis.

Just taught it how to look for YouTube links and embed a little video iframe for them (since they're too big for most people to download)

Here's a locally archived copy of a post I bookmarked with the embedded YT vid.

And yes, it archives images attached to posts too.