Mnemosyne/Anki, (FreeMind, yEd, Gephi, AtomSpace as-moses, RDF bnodes, ONNX,) mind maps, RestructuredRext, MyST-Markdown, todo.txt (TaskWarrior,), StructuredProcrastination, ActivityWatch, Dogsheep, *-to-sqlite, awesome-quantified-self, https://github.com/woop/awesome-quantified-self

But metrics for actual memory retention? I've heard of TinCan xAPI w/ a LRS. nbgrader, Khan Academy exercises, OpenBadges to demonstrate proficiency,