Superfoot
Bill Wallace
Left-leg-only kicker of exceptional speed, using a single chamber from which three different kicks were indistinguishable until the last moment.
Bill Wallace retired undefeated as PKA middleweight champion and did it with, effectively, one leg. A judo injury to his right knee early in his career left him unable to kick with that side at all, so every kick he threw for a decade came off the left — and opponents knew it.
That is what makes him technically interesting rather than merely historic. Knowing which leg is coming should make a kicker easy to defend; Wallace's answer was speed and disguise. He developed a chambered position from which the roundhouse, the hook kick and the side kick were indistinguishable until the last instant, so the opponent knew the leg but not the technique or the target. Timed sources of the era put his kicks among the fastest ever recorded in the sport.
His career sits entirely within American full-contact rules — above the waist only, no leg kicks, no clinch. That ruleset rewarded exactly what he had: fast, accurate, high kicking with no requirement to defend his own lead leg. Under Dutch or K-1 rules a fighter with one functional kicking leg and a permanently exposed lead leg would have faced a very different problem.