Tom and Mini are a pair of NPCs that live in a small camp on Terraformer Island, said camp consisting of a Tent, a Campfire with 4 Steak, and 2 Fences to keep out mobs.
When talked too, Tom and Mini talk about how they used to live in the Colony Ship, but enjoy living there, "where there's danger and adventure!". Other than that, they contribute nothing to the game, except the usability of the structures in their camp.
Tom and Mini are modeled after 2 backers who donated enough to have the game's artist create pixel art of them in the Aground art style. Despite not being in a backer tier high enough to have their own NPCs, they requested the developer to use the pixel art made of them to create NPC cameos of them. The developer agreed to do this. That is the reason the NPCs exist and have such a minimal role, as opposed to the NPCs created by backers in higher tiers, such as Dice and Tindle.