So I have a few suggestions for the game that I personally would love to see thrown in.
Here they are in no order:
-Rare Charm: Obtained by getting 1 of every pokemon (regardless of type and minus events)
Effects: rare pokemon show up a little more often (minor boost)
-Legendary Charm: obtained by getting every pokemon (minus events) in the game(shiny, normal, dark, mystic, shadow, and metallic)
Effects: legendary AND ultra beasts show up a little more often(minor boost)
-Mewtwo new armor works as mega X and Y instead of having the normal Mewtwo on it. (this one is more fun since it wouldn't be canon but I feel having the Megas in it vs just normal Mewtwo would rock)
-Halloween Wooloo, it had devil horns and is spooky. (Sorry i know this one alone is dumb but i had to do it)
-Crystal form pokemon. They have a rainbow hue added over their normal look and have a diamond-like cut. They're immune to crits(alt is they Always crit, Pat's choice) throwing it in for fun since i doubt we'll get any new form since the only "new" one was metallic.
-Negative pokemon. This form will have all their colors inverted, even the line art will go from black to white. I think they should have the chance to confuse the opponent (little less than the odds mystic causes a foe to flinch due to fear) This could be another fun pallet swap to spice up the new forms! There could even be an event where you can glitch 5 pokemon you own to start. (Big jump, I'm not even fully sure this part would work but it could be the 2nd rarest form in the game (2nd to shiny that is) )
Keep in mind I will be adding more things as they come to mind. If you don't like them, don't just say that! Tell me why you dislike it so that it can maybe become better!