Chinese from HelloChinese app is my main one that I consider important, that I want to eventually reach fluency on. But I am also at a point with learning through the app alone where I'm past the "leaps and bounds" phase, I've completed the course both with Pinyin visible and with only 汉字, and so a lot of it is just steadily continuing to learn through the stories and "immersive lessons", and trying to eke out gains in comprehension and memorization and such.

So in order to handle that freshness wearing off, I also mix in learning other languages here and there. The main source of that has been Japanese and Korean through YuSpeak. I also spent some time learning the Cyrillic alphabet; I recommend the app "3 hour Cyrillic by 'Russian Made Easy'" for this, it's both free and it puts the letters in context of words they'd be used in. Then I've made some effort to learn the Arabic alphabet too, but haven't really found an app that clicks well for doing so.

I wanted to get back into French, cause that was my original main attempt at learning a second language before I got into Chinese, but again, haven't found an app that clicks well for it. I originally was learning French through Duolingo but quit it a while back when they pushed the "health system" that penalizes mistakes. Then I tried to get into it through Busuu, both in the past and more recently, but their course design is annoyingly inconsistent at this point, in both content and the length of a lesson.