I am a little bit late, but I feel like my answer will be enriching for you
Italki (of course)
Duolingo
Reverso Context (an outstanding translation app)
Russian noun declension (you type a noun and it will show all it's declension forms singural and plural)
Russian verbs conjugation (same thing but with verb conjugations)
Yazh free (an app that works like a game to find the correct declension of pronouns, nouns and adjectives, it helped me a lot to memorize the declensions but I don't think it is still avaliable to download)