Off Brand Flash And High Speed Sync
Hi, You are right to check carefully.
Certainly many off-brand 3rd party Speedlites that claim 'compatibility', will not offer HSS or Nikon's FP Sync.
Off Yongnuo's output, some offer HSS & some don't. So check very carefully.
Many Metz units include HSS.
Nissin's 866 Mark II includes it.
As does Phottix's new 'Mitros' Speedlite.
Also 'within brand' but discontinued Speedlites usually will include HSS. eg Canon's old 550Ex or Nikon's SB 800 include HSS.
If you get into off camera flash, note that only a minority of RF triggers support HSS (usually those that also offer E/ITTL). Then you might wish to learn about the different but related 'Hypersync' or 'Overdrive sync' etcetc.
I think Mitros for Nikon is available! Cheers