Pokedex Tracker app is for tracking pokemons while completing national dex especially in older games where you have to play multiple games, sometimes you may accidentally invest time in trying to catch a rare pokemon which you may later realised you have already caught in the previous game.
I have colected all the data by scarping of pokemon list in json format the python script for doing so is https://github.com/SatyamAK/Pokedex-data-scarping