I am posting this information and photos on behalf of a forum member allendale65 (Bruce). Bruce sent me an email last night telling me about the birth of 90+ Plains garter snakes. Today I received a couple more emails with the details and photos.
Total born 97 (Possibly and new record) This is still to be documented but is in the process of doing so with the help of Jeff LeClere (herpnet.net)
91 live birth (1 being two-headed)
6 Stillborn (2 being two-headed)
What a great bunch of scrubs. In the 2nd photo I circled the two-headed stillborns in red.

Photo #3 is of the live born two-headed with lower jaw problems. It will be euthanized as it can't survive with this type of deformity.
Photo #4 is pre-birth and #5 is post-birth.
There is also the possibility that the mother is a record length at 43+ inches.