google.com/store/apps/details?hl=en&id=jp.jfkc.KatakanaMemoryHintApp.Id
Android app teaching katakana through mnemonic pictures, animations, sound, and quizzes. Designed for complete beginners learning Japanese writing.
Kanji and kanaEducational gamesApps and toolsKatakanaKanji mnemonicsQuizzesPronunciationBeginnerAppsJLPTHiraganaFree