Not really completely on topic, but there's an app called Kinnu. It's free, and gamifies learning- like Duolingo but for a really wide variety of topics. So far I've done the pathways on learning, ikigai (Japanese concept of reason for living/being), logic and cognitive biases. They have pathways on other things too, like history, various sciences, philosophies, even personal finance (probably the next one I do).
It's a great way to kill 2-5 minutes a day and Ive learned a ton.