I've got a whole stack of very specific tools that probably I've only used once or twice, but made the job much much easier - spring clamps. rotax engine locking tool, MT500 bearing press, MG rear brake cylinder tool, Kawasaki Fork seal tools, Land Rover hub nut spanner, AN braided hose stuff.......

1972 4/4 4 seater, 1981 MGB GT
1984 Harley Davidson Electra Glide, 1990 Kawasaki ZX10