Here is a 15x15 grid with spaces for 225 Pokemon. Let's make a dex. The rules are simple: Post a picture of a Pokemon and it along with its evolutionary line will be added. The first 3 three stage lines will be the starters.
Since there is only 225 spaces, some restrictions are needed:
Only 2 legendary groups (one main and one sub)
Only 2 pseudo lines
At most only 3 mythicals
Everything else is fair game.