Numerous times here at ATS..
But here goes:
MiG-15
MiG-17
MiG-21
MiG-23
MiG-25
MiG-29
Su-7
Su-17
Su-20
Su-22 (From Su-7 to Su-22, generally aircrafts of Fitter series..)
Su-25
Su-27
Mi-8
Mi-17
Mi-24
Mi-25
An-12
At least US has/has had 1 of each of these..
CIA actually operates many Mi-8/17 and An-12s..
For clandestine missions..
And it is also possible that US has/has had:
Mi-2
Mi-4
Mi-6
MiG-19
Su-24
Several different Yakovlev types.. Like 'Firebar'
Etc..
Link!