Avokado - Language learning app
WaniKani - Learn around 1,700 kanji and 5,000 vocabulary words in about a one to two years.
StudySmarter - Your lecture notes, flashcards, summaries, learning with friends, statistics, and even rewards for learning - all in one place and just a click away - StudySmarter.
Kanji Koohii - Remember the kanji; mnemonics, smart dictionary, flashcards, spaced repetition.
LaTeX Cards - The mobile app to create cards to learn your formulas and theorems using LaTeX.
Kanshudo - Master kanji, hiragana and katakana, along with Japanese grammar and vocabulary.