Not sure if it's realistic but I would really like a Kelly Olynyk reunion. With his shooting, playmaking and BBIQ he would be a spectacular fit on this team and is basically a shorter, poor man's Porzingis. He would prove fantastic security in the frontcourt and could play alongside either Porzingis, Horford or Tatum up front without a problem. he would be an immediate 6th/7th man here and would get good minutes, and would be very capable of starting in place of Porzingis if needed from time to time.