There is no physics formula sheet provided by or allowed during the Physics GRE Subject Test. All you get is a table of constants and maybe a few other bits of information. Therefore, unless you plan to waste precious time during the exam deriving equations, you will want to at least memorize the basic physics equations. It is also to your advantage to have memorized other more advanced physics equations as well.

I would suggest that you construct your own personal physics formula sheet and continue to develop it while preparing for your exam. A good start would be to include the basic physics equations found in the link above. Of course, you will want to add other equations to your formula sheet by going through your text books and class notes. Also, as you work through practice physics problems, you will want to continue to build on your physics formula sheet by including essential equations you found necessary to solve practice problems.

Keep in mind, however, that you will not have the physics formula sheet in front of you during the exam so you don't want it to grow into a massive memorization ordeal. Rather, add essential equations that you understand, can memorize, and can readily draw from during the pressure of the exam. Of course, the best way to understand and memorize basic physics equations is to work through their derivation a few times and also to use equations repeatedly to solve problems.

On a related note, with the next link you can find a comprehensive list of physics equations. However, it is definitely not recommended that you try and memorize all of these equations for the Physics GRE. On another related note, you may find it convenient to have a reference book of physics equations like The Cambridge Handbook of Physics Formulas

*(isbn=0521575079)*. However, keep in mind that you will not have these reference materials available during the Physics GRE.