Yes, I think s:link and s:button depend on Seam framework.
The primary purpose of those two controls is to provide versions of the standard link and button that add control over conversation propagation. By its very nature, this is specific to the Seam framework.
I believe that the UI controls that aren't specific to Seam will be in RichFaces, which you can use independantly of Seam. Note that Seam has some legacy UI controls such as s:selectDate, but this has been deprecated in favour of the rich:calendar.
Thanks for the confirmation guys. I just really like the seam jsf control that I want to use it on a plain jsf apps.