Iron golem bait slime farm

The classic slime chunk farm, no potions and no mob duplication in it. You find a slime chunk on Chunkbase, flatten a platform below Y40, and light it to just under level 7 with five torches, which keeps the other mobs out without stopping the slimes. An iron golem stands in the middle as bait so the slimes walk to him, they die on magma blocks, and a hopper minecart under the floor carries the slimeballs along the rails into a double chest. You AFK on a scaffolding tower above it. It only works inside a real slime chunk, and it only works well if every cave inside your simulation distance is lit, which is most of the work.

It has to be an actual slime chunk and it has to sit below Y40. Check the chunk on Chunkbase and start the platform at the chunk centre.
Light every cave inside your simulation distance. Unlit caves fill the mob cap with other mobs and the slimes stop spawning, which is what nearly every "it does not work" comment turns out to be.
彭立忠 built three of them. A dripstone cave and a forest gave terrible rates, a cold ocean gives several stacks an hour with no cave lighting to do at all.
2KGameplay004 AFKs at Y145 to Y150, and if nothing spawns, pillars up to Y160 for 10 to 20 seconds to despawn the cave mobs and comes back down.
gurdev6462 replaces the redstone blocks with levers on the blocks under the powered rails.
The iron golem is a real golem and will pick fights. SoDamnMetal's got into his iron farm and wrecked it.