If you could invent your own Poké Ball...

[Hackbird64]

The Static Ball, which works best on Electric Types, but if it fails, will paralyze the target.

 

[Pilkie]

Evolution Ball:
3x chance of catching a pokémon in its final evolution
1.5x chance of catching a pokémon in its middle evolution (if it has 3 forms)
0.25x chance of catching a pokémon in its first/only evolution.

Big ball: The bigger the Pokemon the better

There is a ball called a Heavy Ball that has its chances increase depending on the pokémon's weight. It is made by Kurt from an apricorn (I think it's black apricorn, but I'm not sure...)

 

[Vyrael]

I would create the Starter Ball. It would be a silver colored ball, like the Premier Ball, and would have three circles on the top half: A green one, a blue one, and a red one. Like the Cherish Ball, you couldn't use it to actually catch a Pokemon, rather it would be the ball Starter Pokemon automatically come in. This includes cases like the Torchic that was just given out and the Gen 1 Starter you get from Sycamore. If it's a starter, it comes in this ball!

 

[Thief]

Time Balls:
Night Ball (form of Dusk Ball); easier capture for Dark types and increased capture rate at night/when it's dark.
Dew Ball (opposite of Dusk): easier capture of Pokémon in the morning or when sunny.

Weather Balls:
Droplet Ball: easier capture of Pokémon when it's raining.
Frost Ball: easier capture of Pokémon when it's snowing or at a very low temperature (should they ever implement day-to-day temperatures in-game).
Overcast Ball: easier capture of Pokémon when it's cloudy.
Storm Ball: easier capture of Pokémon when it's stormy (should they ever implement storms again).

Other Balls:
Mini Ball: easier capture of the very small Pokémon (regardless of weight).
Mega Ball: easier capture of the Pokémon who can obtain mega form (eg. Absol, Pinsir).
Status Ball: easier capture of Pokémon with status conditions.
Colour Ball: a Ball that can be bought in several different plain colours. If the colour matches the target Pokémon it will have an increased capture rate (no higher than a Great Ball).
Travel Ball: easier capture of Pokémon you encounter while riding a bike or surfing.
North/East/South/West Ball: easier capture depending on where you are in the region and which ball you choose.
Champion Ball: a ball that cannot be used to catch wild Pokémon. When you become the Champion, your team will become encased in these new balls that are unobtainable any other way.

 

[Ewery1]

Like a light ball for catching really unheavy Pokemon. There is already a heavy ball, why not?

 

[Chotix]

Id like a Pokeball called the Restore Ball. It could act as an Ultra Ball, but when you catch the Pokemon it's health and status gets fully restored. That way you don't catch a Pokemon that you poisoned and then it die the second you get it in a Nuzlocke Challenge. And you can use your Pokemon the second you catch them and not have to rush them to a Pokemon Center.

That's a heal ball. It has the catc rate of a regular one though.

 

[Blastin'Tyruntz]

Legend ball catches legedaries better than an ultra ball so you don't have to use 5,000,000 of them to catch F**king every legenday ever!!!!! Braagh!!!!!!!!

You could use a quick ball in X and Y and Timer balls or Master balls in the rest of the game...LOL.

 

[Faygrim]

A sword ball for sword dance sweepers. If caught in this ball sword dance sweepers gain +5 points randomly between attack, special attack and speed every level. Imagine Scyther with that advantage.

 

[Melody]

Elite Ball - A ball with a 95% capture rate for any Pokemon equal to or below the level of your highest leveled party member. This expensive Poke Ball can be bought for 9800P each at the shop on Victory Road after you've defeated the champion.

Cute Ball - A cutely decorated Poke Ball that has a decent catch rate, like the Great Ball.

Fairy Ball - A cutely decorated Poke Ball that has an elevated catch rate against Fairy type Pokemon.

 

[Starry Windy]

Adorable Ball, that's designed to have high catch rate for small and cute Pokémon, and that means catching cute Legendary Pokémon is possible with this too.

 

[KittenKoder]

The cage ball, one that's uncomfortable for the pokemon for moves like frustration.

 

[Guy]

Attract Ball. It increases the capture rate when the opposing wild Pokémon is the opposite gender of your own. The effect doubles if you use the move Attract.

 

[Pryze]

Health Ball: Catch rate increases if the Pokemon is within green or yellow HP range. (The higher the HP the higher the catch rate ((Up to that of an Ultra Ball)) And vice-versa.)

Field Ball: Has a higher chance of success if the Pokemon is encountered within a grassy terrain.

Defiant Ball: Catch rate increases with each ball used. (Like a Timer Ball, in a sense.)

 

[Water Gym Leader]

Venus Ball and Mars Ball, Catches Pokemon of Female and Male (Respectively) at a multiplier of 4.

 

[Xander Olivieri]

I had a contest about Pokeballs. If its alright, I'll share the ideas my members had~


50/50 Ball: Has a 50% Catch rate. Flat 50% for everything.

Flare Ball: Increased catch rate when used on Fire Types.

Ancient Ball: Increased catch rate on Ancient Pokemon.

Petit Ball: Increased catch rate the less a Pokemon weighed.

Seven Ball: 77% Catch Rate.

Endurance Ball: Increased Catch rate against Pokemon who are mostly Physical Attackers.

Dual Ball: Increased catch rate when used on a Pokemon with two types.

Contest Ball: Pokemon caught get bonus points in contests.

Evolution Ball: Catch Rate increases based on family line number. First form (Basic) base rate. Increased for Stage 1, and even higher for Stage 2.

Fertility Ball: Pokemon caught don't need special items to breed babies. Eggs appear more often.

Rainbow ball: Increases catch rate for each color in the Pokemon's body.

1up Ball: A Pokemon caught with this levels up upon capture.

Reverse Ball: The weaker your Pokemon is (HP) the better the catch rate.

Rarity Ball: The Rarer the Pokemon the higher the catch rate.

Gang Ball: Increases the catch rate based on number of Pokemon on hand.

Shock Ball: If ball fails to capture Pokemon, Pokemon becomes Paralyzed.

Glacier Ball: Increased Catch rate for Ice types.

Mythic Ball: Increased Catch rate for Dragon Types.

 

[Batty]

Something similar to the Luxury Ball. A very comfortable Pokeball. But instead of raising friendliness easier, it would heal slowly over time in the Pokeball outside of battle. Because it's just so damn comfortable.

 

[Beyond Infinity]

How about a Pokeball based on Magikarp, the Magiball? No real effects/benefits, but it just looks a bit like a Magikarp. Because deep down, aren't we all Magikarp at heart?

I had an image, but I need 15 posts...

 

[braixen]

Lol I'm a sucker for colorful things, so I would just make regular poke balls available in different colors other than red. OR have those pokeballs do with a pokemon's typing, giving it a slightly higher catch rate. Like yellow would go with electric, and so on.

 

[Karinmo]

Infinity ball.
The ball changes its color based on the surroundings and Pokemon. This ball would never go away. You only need one, and it acts just as a regular ultra ball. You receive it near the end of the game.

 

[Beyond Infinity]

How about a Pokeball based on Magikarp, the Magiball? No real effects/benefits, but it just looks a bit like a Magikarp. Because deep down, aren't we all Magikarp at heart?

I had an image, but I need 15 posts...

Just an update, since I was bored, I made the Magiball. Or Karpball. Prefer Magiball.

Look at that majesty...