The Hawker Hawfinch was one of a number of fighter aircraft designed to replace the Armstrong Whitworth Siskin and Gloster Gamecock, but it lost out to the Bristol Bulldog and never entered production
The Hawker Harrier was one of a number of aircraft designed to replace the Hawker Horsley bomber, but after an expansion of the specification to include a role as a torpedo bomber it proved to be badly underpowered and never entered production.
The Hawker Tomtit was an elementary trainer designed as a possible replacement for the aging Avro 504N but that was only produced in small numbers
The Hawker F.20/27 was a single-seat fighter aircraft that was the direct precursor of the very successful Hawker Fury, and that differed mainly from the latter aircraft by using a radial engine.
The Hawker Hornet was the prototype for the Hawker Fury, one of the best biplane fighters to see service with the RAF.
The Hawker Hoopee was a radial powered naval fighter that despite undergoing a prolonged series of trials never entered service, being superseded by the inline-powered Hawker Nimrod
The Hawker P.V.3 was a fighter aircraft designed to satisfy Air Ministry specification F.7/30, but that was made obsolete by the 1933 issuing of the specifications that led to the Hurricane and that never entered production.
The Hawker P.V.4 was a general purpose aircraft and level bomber designed in response to an Air Ministry specification of 1931, but that didn't make its maiden flight until 1934, by which time interest in the entire specification had faded.
The Hawker Hotspur was a turret fighter similar to the Boulton Paul Defiant. Although it reached the prototype stage, Hawker's factories were all fully committed to other aircraft, most famously the Hurricane, and the Hotspur never entered production.