Greece Article 5A (the Greek Non-Dom) offers a fixed annual tax of €100,000 for individuals who become Greek tax residents, covering all worldwide income. No questions about where the money comes from or what type of income it is.
This is different from Article 5B. 5A is for high-net-worth individuals (sweet spot above €1.4M annual income) who want certainty. 5B is for retirees. Both require 183+ days/year in Greece and a valid residence permit. Both run for up to 15 years, non-renewable.