I have the following network blocks with commercials and bumpers containing two pilots for unproduced series which as far as I know only aired once each:

WJBK CBS Detroit, MI 4/13/83 (2 Hours)
1. CBS Special Presentation – “Kraft Presents The 25th Anniversary Of
The Country Music Association”
2. CBS Special Presentation – “Johnny Garage” (Pilot to failed series
starring Ron Carey)

KCRA NBC Sacramento, CA 8/4/88
1. Cheers – “Airport V” (Rerun from 2/25/88)
2. Channel 99 – “Pilot” (Starring Marilu Henner with guest star Ron Howard)