Yes, there are Blackjack card counting apps. Whether they will help you is a totally different story. RNG blackjack games are virtually shuffled after each hand, making card counting much more difficult. In live Blackjack games, typically 6 to 8 decks of cards are used, reducing the edge counting gives you. Additionally, while using your brain to count is fine, using an app while gambling will likely be considered as cheating and void all winnings.