The problem with these specialty screws is that they're ONLY used for certain things. I don't think I've seen a tri-wing screw or a gamebit screw outside of the video game market.
Still not the most annoying I've come across. you can at least purchase screwdrivers and bits for them. Worst ones? The triangular screws used in the assembly of fast food toys. I can not find a bit for those. Normally it'd be a non-issue but in a case of a toy using batteries(lights, LCD games) the batteries are often not replacable. I had a Sonic LCD game with a dead batteyr and had to drill the heads off the screws to open the thing up.