When talking with a friend, the idea of boots that have different abilities came up. To compliment the Backer Speed Boots (and the unimplemented Speed Runners), these boots would be equipped on your hotbar and give unique abilities. Visually the boots would not appear on your model, but would have a particle effect (like Speed Boots and the Ice Potion).
Spike Boots
Aggressive boots that allow you to Goomba-stomp other players and bounce off their heads. With PVP disabled, you harmlessly bounce off the other player’s head.
Heavy Boots
Boots that increase your gravity / fall speed. When in water, you sink to the bottom instead of swimming. Instead of slipping on ice, you are able to walk normally.
Spring Boots
Boots that allow to jump higher and further. Comboing jumps allow to gain more height and distance (similar to the Pogo Stick). Crouch-jumping causes you to leap further while decreasing your jump height. Crouching on the ground allows you to charge up jumps.
Roller Skates
Sprinting while pressing the A and D keys in rhythm will cause you to move faster.
I’m not sure which store would best suit these. Unless the Appearance store were to have a “Functional” sections (which would also contain the Jetpacks), the best options seem to be the Toy store or Rob’s Imports.
Spike Boots (my favourite) would add some fun PVP gameplay while the Spring Boots and Roller Skates would add more mobility options. Heavy and Spring Boots would both allow players to make unique Condo obstacle courses and Roller Skates would allow some more skill-based racing.