I made a personal challenge for myself: do as much as I can without leaving this island. I didn't spawn on it so I brought a birch and an oak sapling from the mainland, along with a couple of sugarcane, but it turned out the island had one acacia tree and some sugarcane already growing on it. I'm yet undecided on how much mining I'll allow. So far, I've dug enough to have a few stacks of cobble and some iron.
The cows, sheep, and pig all spawned naturally on the closer end of the island that is a savanna biome.
I'm not sure how far I'll take this since I just came up with it while bored. We'll see. Next up, a mob farm. Well, waiting for the trees to grow so I can get the blocks for a mob farm. And maybe a house of some kind.

Ugly as fuck? Yes. A style of play I've never done before? Also yes.