I&#x27;m pretty sure the go to is Anki - <a href="http:&#x2F;&#x2F;ankisrs.net&#x2F;" rel="nofollow">http:&#x2F;&#x2F;ankisrs.net&#x2F;</a> which is based on Spaced Repetition - <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Spaced_repetition" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Spaced_repetition</a>