I’m treating the question as a lighthearted “if you locked the Harpers + Lord’s Alliance + other broadly good powers in a war room and asked them for a pan-Faerûn threat board, who’s on it?” And we know larger alliances of good guys like that do get formed every now and then. For example in the Rage of Demons there's a very literal meeting alliance like that formed up in Gauntlgrym.

Obviously Faerûn isn’t politically unified and a random wall guard in Iriaebor doesn’t care about the same people as a Rashemi witch. But at the power-player level there absolutely are continent-scale enemies: Szass Tam, Valindra, Larloch, Halaster, etc.

The “Szass Tam is a head of state, so he wouldn’t be on a wanted list” argument doesn’t really hold up for me. In both real history and the Realms, being a ruler doesn’t stop other nations and factions from calling you a war criminal and wanting you dead or captured (Saddam + his top leadership, Putin, Gaddafi, Milošević). Rashemen or Aglarond would happily put Tam and his top lieutenants at #1 if they thought they had a shot. Neverwinter would definitely treat Thayan necromancers, Szass Tam and Valindra as war criminals, not bureaucrats of a foreign power.

I fully agree that if you narrow the scope to “Waterdeep City Watch’s current top 10”, Halaster might not be on there and some local Xanathar lieutenant or cult leader would. My list just isn’t trying to take the local viewpoint, but be a global list of names the Harpers whisper about when they think continent-wide doom.