For the sky pirates faction server, I have some ideas for additional weapons and stuff. In no particular order:
Cannon: consumes 1 gunpowder and 1 cannonball (crafted with iron or something idk) to shoot an explosive projectile at a ship. Powered by redstone and shoots straight forward, basically a dispenser with more range.
Bomb: a handheld explosive, can be thrown or shot from a dispenser. Much less range than a cannonball, making it dangerous to use.
Parachute: wear on your back, hold space while falling to deploy, lets you fall slower and cancels fall damage. Very useful if you're falling from a high place. Not so useful if there's only void below you.
Anchor: a very heavy block suspended from a chain, can be powered with redstone to raise or lower. Can be used to attach to a land mass.
Rope ladder: a ladder that works in the air, can be right clicked to drop so you can climb down on things.
Grappling hook: Can be thrown by hand, or shot from dispensers. Grapples on to something and either pulls it towards you, or you to it.
Life preserver: a compressed-air mechanism that places a single gold block below your feet even if there is no block to place it on. One wonders why the design requires a gold block and not something cheaper, like wood. Perhaps it gives an incentive for passing ships to stop for a stranded pirate, or maybe the inventors didn't want people sprintjumping through the air leaving ugly stacks of wood everywhere. Or there's some technical reason that only engineers get.
Catapult: can launch blocks. Adjust the angle by right clicking, then power with redstone to fire (this has the possibly-wanted side effect of lighting any TNT you may have in there).
Cartapult: an ingenious combination of a minecart and catapult. Can launch players into the air, allowing raiders to land on ships, kill the crew and take everything without the risk of Voiding the ship's precious cargo in a cannon fight. Or miss the ship and die hilariously.
Harpoon: Improves upon the original design of the lead, by adding a pointy stabby part. Attach to a fence post and throw by hand. Lets you latch on to other ships, mobs (such as dragons or space whales), or blocks. Note, space whale hunting is now illegal due to how endangered they are, but many believe that the weird anime clans continue to hunt them.
Rum: a magical substance created from fermented sugar. In excess, it is able to give players nausea and a lack of coordination, as well as making all other players seem 500% more attractive. Pirate tradition holds that this drink's influence inspired the creation of the cartapult.
ENDAR: shows you any ships in your nearby vicinity, using the frequencies emitted by ender pearls or something like that. Fun fact: This technology was first used by a British clan. When nazi griefers called "hacks!" and demanded to know how they could see their ships, the Brits replied that they eat a lot of golden carrots. This meme led to the
false belief scientific fact that carrots contain the magical property of night vision, now a staple in modern alchemy.