I would love an Eviolite Ball, a ball that catches Pokémon with a x2 if they are not evolved all the way. It would be a light purple and translucent ball.
I enjoy the idea of a Shine ball, that would give a 3x catch rate when catching shinies.it would have a bright Green top and a black bottom to mirror the normal pokeballs.
The Bulk Ball. The ball would have an equation to determine the catch rate, just like the Weight ball. It would be based off of the Physical Attack and Defense Stats of the Pokémon. If Attack=a, Defense=d, and Natures=n, the equation could be like this. ((a+d)/2)-n
How about a ball that randomizes its catch rate. I don't why I like it, but I guess I'm a bit of a gambler. It could be like a "jester ball" or something.
I would think of an elements ball , like we have dive balls and nest balls, so a ball for other types like a fire ball or a pixie ball, each one for those pesky low catch rate mewtwos out there to have a psi ball that has a cool exterior to the typing and the balls have an effect that goes with that element.
Fashion Ball? Functionally the same as a Poke/Great/Ultra Ball, but available in different colours, like a variant on the Premier Ball. It doesn't have any special features, except letting you put your Pokémon in fancy, colour co-ordinated balls.
Maybe a ball for younger Pokémon? It would be great for a breeder; as soon as the Pokémon is born, they catch it in the ball, and it grows with the Pokémon. Or it could be a temporary sort of ball, designed especially for a breeder, so that they could keep track and take care of the Pokémon they breed until it grows old enough to be adopted by a trainer who will catch it with their own ball.
I would make the Multi Ball. It has a 2x catch rate of capturing a Pokémon in a horde or double battle when the one Pokémon has called for help.
The Techno Ball! 2x catch rate for both Electric and Steel types! The design is similar to that of Beast Balls, except for the dark blue is dark grey, the net like light blue part is steel gray, and the other gold part is blue lightning bolts. The entrance animation would be blue electric bolts going outward, while the exit is the bolts going on!
