Our partners PreflopHero have launched a version of their preflop trainer for 6-max cash game and until May 21, anyone can use it for free https://cash.preflophero.com/
Main features of the app:
1. Training in a simulator of a real 6-max cash game on the preflop
2. The ability to create your own charts and train them
3. Error analysis in training sessions
4. The application is also adapted for mobile devices