This page lists all of the Slime Gate locations currently available in the game.
There are 8 standard gates, plus 3 Vault gates which can only be accessed after viewing the credits, totalling 11 gates.
Gates in The Dry Reef
The Indigo Quarry
The Moss Blanket
The Beach
Ring Island Vault
Gates in The Moss Blanket
Feral Path Vault
Gates in The Indigo Quarry
Ash Isle Vault
Gates in The Ancient Ruins
Moss Blanket Entrance
Indigo Quarry Entrance
The Glass Desert Warp Station
Gates in The Glass Desert
Eastern Slime Gate