rubber skirted bass jigs ususaly imitate crawfish or something else tasty on the bottom, bucktail jigs usually imitate something along the lines of a minnow, so do float n' fly jigs. if you dont know what a float n fly jig is, its a small light jig (as pictured) that you put under a bobber and fish suspended in the water colomn. then there are bare jig heads where its just a hook w/ a lead head. you usually put somekind of soft plastic on these (curly tail jig, small minnow lookin thing, crawfish soft plastic...) and you just use the jig for casting weight and to sink the bait to desired depth.