Useful but expensive – Russian Grammar - Русская грамматика Review

The tables are useful references. The section on verb conjugations needs more examples; only one verb идти is used to show present tense conjugation, and the remaining verb conjugations are also lacking. I would recommend purchasing this app if you want to study on the fly without a book but it is overpriced.
Review by Budwer on Russian Grammar - Русская грамматика.