Best Aircraft never to enter service

Whats the best airforce you can but together out of aircraft that never entered squadron service or got beyond prototype stage, even of the drawing boards will do. For me…
Strategic bomber- XB70 Valkyrie
Tactical strike/recon- TSR-2
Interceptor-YF-23
Multirole- IAI Lavi/F16XL
CAS/FAC- A10B (two seat allweather/night version of the A10A)
Attack helicopter- AH56 Cheyenne
Strategic Transport- AN225(only 1 and a half built)
AEW- C130AEW proposal (cheap AEW)
Maritime chopper-Sea Apache (proposal for US Navy and Marines. An Apache with the F/A18 Hornets cockpit electronic to give it multirole abilitiesincluding A2A with AMRAAMS. Probably best that didn’t make it to service, bit of an expensive and useless deathtrap.
Any other proposals?