I don't know why this would be worth it, but it's cool.
Boosters would be obtained by finding them in chests in the Dungeon or the Airship. Boosters could also be obtained via drop party by admin or something. So let's say I'm in the Airship looking for chests, and I find the jackpot of boosters.
As you can see, boosters are little enchanted books. They each have different abilities and can be customized.
As you can see, we've got one booster that has a Speed effect on it and another that has Protection, but also Slowness.
Here's a list of different boosters:
Speed - When you have a speed booster equipped, you get a Speed I potion effect(or attribute)
Slowness - When you have this equipped, you get Slowness I(or attribute)
Sharpness - When you have this equipped, all of your attacks do 10% more damage.
Protection - When you have this equipped, all incoming attacks are reduced by 10%
Haste - When you have this equipped you will gain the Haste I effect.
Weakness - When you have this equipped all attacks from you are reduced by 10%
Luck - Gives a 10% chance to get mob drops or player heads. It also acts as Fortune I on any tool.
Angel's Food - As long as this is equipped you will not lose hunger. This can only be used by Premium+
Obsidian Skin - As long as this is equipped you are immune to lava and fire.
Particles - There are boosters for each particle effect that donors can get. They can only be used by their respective rank. This is just so you don't have to do /effect all the time.
Now, some of these sound overpowered. That's why you can have 2 powers on one booster. Most of the time they are paired with a negative effect such as Slowness or Weakness. If you are really lucky you can get one that only has one positive effect. These are uncommon though.
How do you equip a booster? Here's a little example I made.
So there it is. When you type /boost it will open a Hopper GUI like shown above. The red spaces mean you cannot hold that many boosters. Lower ranks have less boosters.
Citizen & VIP - 1 Booster space
Premium & Exclusive - 2 Booster spaces
Elite - 3 Booster Spaces
Supreme - 4 Booster spaces
Ultimate - 5 Booster spaces
When a booster is in the slots, it will activate. Boosters are not dropped on kill but the booster will not be able to be used for one hour after death.