Some of you just enjoy beating the crap out of mobs, but I enjoy to use permanent structures to allow mass resource farm (plus, my game lags & can't perform proper kiting). Here are some I often use.
1. Feather farm
Turn catcoon into automated bird killing machine
Used materials : 5 seeds, feather hat, 6 rocks (for 4 walls), 1 cutgrass(to lure catcoon)
Pro : Cheap, not hard to make, best way to gather feathers without Wickerbottom's books & weapons
Cons : Catcoon falls asleep at least once a day, and can be slightly frustrating
2. Pig & Bunny Farm
An "oven" that can cook multiple pigs & bunnies within few seconds
Used materials : 2 fossils, 12 rocks (for 12 walls), 6 grass, 1 rot/carrot (bait), waterballon or ice flingomatic
Pros : Possibly cheapest & fastest mass slaughter farm.
Cons : Fire hazzard, Ice flingomatic can be costly (but don't we already have like one ice machine besides pig/bunny village?)
3. Mole Farm
Mole farm using cave duplication instead of expensive bundling wrap dupe
Used materials : Hammer, couple of rocks
Pros : Easy way to multiply moles for those who can't kill bee queen
Cons : takes 2 days for multiplying, much slower than bundling wrap method
4. Monkey Farm
Using monkey's curious george trait to kill them
Used materials : rocks (depends on how big the trap is), 1 bait (can be anything), 2 fossils, weapon/cane
Pros : Can safely dispatch multiple monkeys without much difficulty
Cons : Unable to build farm near the monkey pod as putting down bait is near impossible
5. Varg Farm
Turning Varg farm into hound factory
Used materials (in video) : 18 rocks (for 13 walls), 8 pinecones, 14 fossils, 1 lureplant bulb, panflute
Pros : If you know bit of kiting, you can get endless supply of teeth, gem & monster meat
Cons : It is not THAT cheap (though can be used indefinitely), and the danger exists, since you do have to kill hounds yourself