Scrapper Turrets are the first type of Scrapper encountered in the game. They appear in the Ancient Crater as a secondary defense system against intruders in case the Ancient Sentry Towers couldn't stop them. Scrapper Turrets appear on floors and ceiling and periodically fire shots at Gale. They're fairly durable, but two charged attacks can take them out easily.
Scrapper Drones are basically flying versions of Scrapper Turrets that appear within the Phoenix Lab and the secret area in Adar's House. They fly towards Gale in short bursts of flight and shoot when they're not moving. Scrapper Drones can be hard to hit because they fly away from Gale when she gets close to them, but they can be knocked out of the air with any projectile. For this reason, the easiest way to deal with a Scrapper Drone is to hit it with a shot from the Slingshot. Alternatively, you can also use the Artifact on a Drone to turn off its engine and bring it down. After it falls on the ground, you can go up and mash the attack button until the Drone is destroyed.
Scrapper Globes are the rarest variety, only seen during the battle with the Computer Guardian. The Computer Guardian always spawns four Scrapper Globes (six when its health is low) for its first attack. The Scrapper Globes bounce across the floor for a few seconds before releasing chains to attach themselves to the floor and ceiling. The Globes then ride along these chains and occasionally release electric surges that run down the chains and across the floor. They're the weakest type of Scrapper and can be destroyed in one hit with a melee weapon, although it's recommended to use the Javelin on the ones that are too high for Gale to reach.
All three Scrapper enemies will be returning in the remake, with new graphics and names.