What kind of mob farm should I make maybe a passive mob farm? One of those fancy outrageous iron farms idk I’m bored and want something cool to build tell me what you think I should do
Make a huge rainbow sheep farm. Make it look like a huge rainbow, and inside each cloud of the rainbow, put sheep in there, one cloud for shearing, and the other for lambchops and breeding. You can transfer them via the rainbow with water
Wild Nether and make a massive auto Wither Skeleton Head Farm. Would love to use it and then nearby have a spot to slay Wither Bosses. Have not really looked at the video but something like this. https://youtu.be/8u66ktVn0f4
Only problem with wither skeleton farms is that you have to deal with the area around the farm to make it even the tiniest bit good. If you're looking for a good mix between profitable and simple, I would suggest either an iron farm or a blaze farm with multiple spawners.
Just as a side note: most spawning-based farms from youtube are terrebly inefficient on EMC (or in general) due to our spawning algorithm being different: I would defenetly suggest looking into that too. Also, multi-village iron farms don't work really... Tango's Iron Phonix does kind of work, as it doesn't need to be set in the spawn chucks, but it will peobably be broken in 1.13 due top slime blocks no longer being an oppaque sollid block.