The one(s) whose language(s) you already speak, unless you're rich enough for an investor visa: https://en.wikipedia.org/wiki/Immigrant_investor_programs#In...
(While Germany may be tempting especially with all the English used in tourist areas, be aware it's not for nothing that native German speakers use in real life a phrase which translates as "The German language is difficult").
Most of the EU, but not Denmark or Ireland, also theoretically have the Blue Card scheme; but I say "theoretically" because that's a bureaucratic streamlining, the actual granting is still done at national level and from what I've heard different countries grant them at different rates: https://en.wikipedia.org/wiki/Blue_Card_(European_Union)
