Shaft Lamination
Dunlop Maxply (1932)
Lamination with 20 layers perfected strength and flex
Anti-Vibration
Snauwaert Caravelle (1971)
Snauwaert added slots in the shaft to reduce vibration feedback
Graphite Reinforcement
Dunlop Maxply Graphite (1976)
Slazenger and Dunlop both added graphite layers to reduce flex around 1955
Metal frame
Wilson T-2000 (1967)
Lacoste invented it, but Wilson introduced it to Conners who won with it!
Internal String Bezel
FH Ayres Davis Cup (1920)
Ayres might have been one of the first to make a bezel to stop strings breaking
Extended Length/BiHander
Slazenger Bihander (1967)
Slazenger and Dunlop both developed rare two handed versions, predecessor of XTD
Mid Head Size
Donnay Mid 25 (1975)
Donnay may have co-invented the mid-head size of 95″
Composite Frame
Head XRC (1980)
Volkl Zebra was likely the first fully synthetic (fiberglass) racket in 1972 with Yamaha not far behind. Everyone else copied
Rubber Grip
Dunlop Blue Wing (1937)
Dunlop invented the rubber grip
Grommets
Head Vector (1975)
Howard Head may have helped invent plastic grommets vs string breakages