Hanzio is a free Chinese dictionary and study app that turns characters into long-term memory. Every word comes back four ways: type its meaning, type its pinyin, draw it from memory, and recognize it by ear. No self-grading, and each mode is scheduled on its own. The dictionary has 150,000+ entries with stroke order, character breakdowns, and frequency data.
Plus, an HSK grammar and stories course and an offline camera scanner.