There are no standard rules for what goes in box 14, and no standard codes or abbreviations. The employer can put pretty much anything they want in there. If you're not sure what something means, you have to ask your employer.
As Critter said, S125 probably refers to a Section 125 cafeteria plan. But the proper category to choose in TurboTax depends on exactly what it's for. A cafeteria plan can include many different kinds of benefits. You have to ask your employer exactly what the S125 amount is for. Then you'll be able to figure out how it should be treated on your tax return, or whether it affects your tax return at all. My guess is that the category is going to be "Other," but find out exactly what the S125 represents.
When you say a "Washington State W-2" do you mean that you work in Washington State, or that you are an employee of the state government?