In my personal system, I tag facts by sub-topic and the daily reps are ordered so that facts of the same sub-topic are shown consecutively to avoid context swit

In my personal system, I tag facts by sub-topic and the daily reps are ordered so that facts of the same sub-topic are shown consecutively to avoid context switching (eg. AAABBCCCCD not CABCCDBACA). In addition, there is logic so that after the mandatory daily reps are done, it will show cards that are close to the due-date (eg. within 0.25*LastInterval), again batched by sub-topic. This lets me efficiently get reviews out of the way on days when I have time to do so, without deviating too far from the basic SRS philosophy. As a result, for mature cards, I end up focusing on a small number of sub-topics on any particular day. I find that works a lot better. All of this is trivial to implement - I think it's best to create from scratch and specialize it for one's own domain instead of using a pre-existing solution. In my case the relationships are straightforward (sub-topics) but in others it might be more fuzzy. Programmatic fact-generation/deletion is also something I put a lot of effort into (again, domain-specific).