Minecraft terrain, roguelike dungeons, and No Man's Sky planets all come from the same place: rules, not hand built content. If you strip procedural generation down, nearly everything ships on three algorithm families.
Noise functions. Perlin and simplex noise give you smooth randomness, which is exactly what terrain wants. Sample 2D noise for a heightmap, layer a moisture map on top, threshold it, and you have biomes. Almost every survival game terrain starts here.
Dungeon algorithms. Binary space partitioning splits the map into guaranteed non overlapping rooms. Cellular automata smooths random noise into organic caves. Random walks carve winding tunnels. These are old, simple, and still what most roguelikes run on.
Wave function collapse. The newest of the three, and the one that feels like magic. You hand it a small example layout and it generates arbitrarily large output where every local neighborhood matches your example. It is constraint solving dressed up as level design, and it means the generator follows your art rules without you writing them out.
The part most tutorials undersell: determinism. Drive everything from one seed and the same seed always produces the same world. Bugs become reproducible, players can share worlds as a single number, and your save files shrink to almost nothing.
I keep a full guide covering these algorithms, engine support in Unity, Godot and the web stack, and good first projects here: https://www.abratabia.com/procedural-generation/
What did you build your first generator with? I am collecting good starter project ideas.
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