No. 1: De'Anthony Melton
The Toronto Raptors saw a real need at both backup point guard and point of attack defense, and to their credit they addressed it, adding a pair of players who check both boxes. That doesn't mean they committed real resources to it, though, adding a castoff in Davion Mitchell and the 45th pick of the draft in Jamal Shead.
In addition to neither playing having much of a ceiling and a questionable floor, they also are small enough to be position-locked at point guard, essentially stuck playing behind Immanuel Quickley. Instead, the Raptors could have signed a player who is better than either of them by multiple degrees, and at the same time has the size and shooting ability to play next to Quickley in the backcourt.
That player was De'Anthony Melton, the former Philadelphia 76ers guard who signed a one-year contract at the Mid-Level Exception with the Golden State Warriors. There he will get to play alongside Stephen Curry, but he neither signed with a title contender nor is guaranteed to start.
Could the Toronto Raptors have enticed him with a guaranteed starting spot? Or, if they had let Bruce Brown Jr. walk in free agency (or re-signed him to a lower number) could they have outbid the Warriors by a few million and locked Melton up on a long-term deal? These are reasonable questions; the Raptors are not a great team right now, but it's not like he got a lucrative deal to join a title contender; the Warriors are going to be battling for the Play-In Tournament next year in a loaded Western Conference.
Melton's shooting and cutting ability would be ideal next to the on-ball stars in Toronto, and he was one of the best perimeter defenders on the market. We were discussing him as a target for the Raptors since well before free agency, but unfortunately the Raptors decided to slam the door on using cap space and he signed with the Warriors.
Melton would have been a perfect free agent signing for the Raptors, and perhaps will represent a major missed opportunity for the franchise.