Bones HardCore Bushings are probably the best bushings available for your regular street trucks. With a patented harder urethane inner and "cup washer" encased in a softer outer, these bushings have insane rebound and will transform your skateboard trucks.
They are a bit too small to fit more longboard / RKP style trucks effectively unless you shim them out, but for regular street trucks like Independent, Thunder, Venture or Destructo, these are worth every penny.
Each pack comes with four bushings and a pair of flat washers to fit, enough for a whole board.
Bones don't specify their durometers with these bushings but we'd go soft for lots of turn, medium for a regular turn, and hard if you want to keep things stable.
Roadside Cone: 11mm tall
Boardside Cone: 14mm tall