These are just my opinions. Other People might have different opinions about these planes.
My list of obsolete planes of WW2:
Douglas TBD-1 Devastator
Bell YFM-1 Airacuda
Grumman F4F-Wildcat
Brewster F2a Buffalo
Grumman F3F
Nakajima Ki-27 Nate
Aichi D3a1 Val
B5n Kate
Ki-43 Hayabusa
F1M Pete
G4M2 Betty
And especially; the Blackburn Skua.