Skateboard SRS is spaced repetition app that helps you to learn new tricks and maintain old ones. Furthermore, it holds you accountable to do the tricks that you want to be able to perform.
One thing that I find valuable in this app is that you can generate different versions of the same trick by selecting various tags, that you create yourself. So you dont need to type in manually that you want to do a nolli/switch/normal/fakie 5050 on a ledge, a rail, or a curb.
You are able to view all the tricks that you want to do at this point and the ones that you need to repeat in the future.
Additionally, you can create your custom pre tags, post tags, and obstacles.