Cowboys mock drafts have been holding relatively stable over the last few weeks. In general, there is a group of mocks that center around cornerback, specifically either Patrick Surtain or Caleb Farley. Then you have the more wild card mocks, but one of the common positions that get mocked to the Cowboys outside of cornerback is offensive tackle.
With the Cowboys offensive line having its struggles with injury last season, and with tackle Tyron Smith missing time regularly over the last four seasons, offensive tackle has become a priority. So the position regularly shows up in mock drafts, and the specific offensive tackle is usually Rashawn Slater.