I would like to introduce you my new Android app: My GTA V Map.
It will help you to track what collectibles you got, and how to get the remaining ones.
Just select any of them, watch the video of how to get it and mark it as collected. That's all! You can select among 3 kinds of map: Atlas, satellite and roadmap so locations are easier to spot.
You can find more about it here: My GTA V Map on Google Play
I recommend you to first import manually collected items from Social club as a starting point.
I'd be glad to hear any suggestions or comments.
Hope it helps!