Original Commentary
Enter new challenger... miss Sandra was my only real requirement I had about this arc. For now, just know her as Patrick's little sister. -Isabel

Modern Commentary
We've got:

Sandra here in You Say it First
Shaundra in Spare Parts
Shandra in The NDU

We also, unrelatedly, have the similarly named:
Cassandra in Nicole and Derek and 100% Cat
Cassie in Grover Hills, Namir Deiter, and Nicole & Derek - Terrence