The Tusq picks are a proprietary hardened delrin, like a Tortex. I got kinda fanatic about plastics when I was searching for/making the perfect large, light steel guitar bars, and ended up learning more than will ever do me further good.... The original Dunlop red Jazz I, II and III are made out of a high-grade hard nylon. Then to make them even harder for the black ones Dunlop adds powdered silica, AKA glass AKA sand. Dunlop's wunderbar "Tortex" material is a delrin analog hardened with silica, as is Clayton's "acetal" though that's much softer than Tortex. Clayton & Dunlop make their own picks, Fenders are of course sourced Asian these days but I don't know where. Everything "Planet Waves" are just re-branded Dunlops, there are some who claim Dunlop is making a slightly softer "Tortex" plastic for Planet Waves, though I don't hear it. Different gauges, for those convinced that a .94mm pick is different enough from a 1.0mm or .0.9mm to matter (I am.)
Clayton and Dunlop are both making fine new picks out of a "space-age" plastic called Ultem, it doesn't notch, chip and wears very slowly, they have to make them transparent because if you don't lose them you'll never need to buy more. The ultra-expensive Blue Chip picks, Red Bear casein picks and that sort simply have nothing in tone or feel over ultem, IMO. Except that tried, trusted and ludicrous formulaic con game, "If YOU can't hear the difference YOU don't DESERVE one..." And then there's the old celluloid, which is still perhaps the "best" sounding if you play with enough treble and gain to elicit pick click no matter what else you do about shape, technique etc. And it chips, dents and wears. Everyone should seek out a D'Andrea 1.5mm "PLEC" celluloid at some point in their life.
Attaching handles of various sorts is popular, either gluing other pieces of picks or casting epoxy (skateboard grip tape! Rubber sheets! Cork is a golden oldie...) Attaching any sort of stiffening handle & fiddling with differing shapes and extensions of the handles and the tip shapes allows you to vary the flex, "release" and tonal characteristics to a deeply obsessive degree. And a pocket full of different picks will give you a far greater amount of tonal variation than a shoebox full of every different brand of "P.A.F." pickup ever made. Did I ever mention I was cheeep? :laughing3: