Although a few thousand isotopes have been discovered, the limit existence is only known for the lightest elements. Unfortunately, there has not been a comprehensive compilation of all the discoveries. A project has been undertaken to find all of the first discovery papers. Claims of discoveries were investigated and verified, and first publications are listed at http://www.nscl.msu.edu/~thoennes/2009/discovery.htm. In this project, I investigated isotopes with 66 <= Z <= 70 and 81 <= Z <= 98.