Ehh, I used Drops, on the free tier it only gives you 5 minutes/a day to use it, I think it can be okay as a supplemental tool, but not as a main learning app
They do offer some small languages, like Ainu and Maori, so that's nice
That's interesting. Do they also mention / teach grammar rules in the app? I would love to have those in an app and not always look it up in my books / online.