Cecil John Charles Street was both John Rhode and Miles Burton, so it's cheating a bit to allow him two sets of bests, I suppose, but then we are talking 140 novels! I think the man deserves it.
Best John Rhodes (all with Dr. Priestley)
The House on Tollard Ridge 1929 classic case of Rhodian murder gadgetry and some good spookery
The Davidson Case 1929 Early use of a famous gambit, which Dashiell Hammett thought unfair, with some interesting philosophical reflections
The Claverton Affair 1933 classic poisoning case in gloomy house with spiritualism too
The Robthorne Mystery 1934 dares to use twins, in violation of Father Knox--can you go to Hell for that?
Poison for One 1934 another classic poisonings
Shot at Dawn 1934 the last word on tides
The Corpse in the Car 1935 yet another classic poisoning with some acute satire
Death on the Board 1937 classic multi-murder case with a multiplicity of ingenious murders, with some acute social commentary
Invisible Weapons 1938 a rare venture into locked rooms
The Bloody Tower 1938 family curses and rural squalor
Death at the Helm 1941 another classic poisoning, with serious treatment of love triangle
They Watched by Night 1941 classic wartime tale
Death in Harley Street 1946 death that is neither accident nor suicide nor murder???
Best Miles Burtons
The Secret of High Eldersham 1930 a classic treatment of the witchcraft theme
Where Is Barbara Prentice ? 1936 high jiggery pokery with a body
Death in the Tunnel 1936 if you want to stage a railroad tunnel murder, this is the way to do it
Death Visits Downspring 1941--wartime mystery; the butler didn't do it but it was done to him
Murder M. D. 1943 (strong character interest in this one)
The Three Corpse Trick 1944 striking complexity in a tiny habitation
The Cat Jumps 1946 one of the early cat mysteries and a locked room situation
Situation Vacant 1946 Why do the secretaries keep dying in the village?
Death Takes the Living 1949 not his most brilliant plot but an interesting look with disgruntlement at post war England
Ground for Suspicion 1950 excellent postwar provincial mystery
Murder in Absence 1954 partially a cruise mystery, though it's a tramp steamer
The Moth Watch Murder 1957 notably unique specimen
Bones in the Brickfield 1958 excellent late village mystery involving a found dinosaur fossil