Commonly on oak floor, the best choice for stain is pine, birch ash; maple is not a good choice for staining or and dark color wood. We usually use minwax stain to put down and recoat. You can find it at most hardware stores. There about 22 different type of color to chose from on minwax.com . It is best to chose a color in mind first then test it on the existing floor to see which on is best to your preference, because different floor produces different color and usually the can is always lighter than what is going to be the final result.