Estonia

Estonia's draw is its company tax: an Estonian company pays nothing on profit it keeps and reinvests, and 22% only when it distributes, with no further tax on the dividend for the shareholder. For a person who actually moves there it is an ordinary 22% flat-tax, worldwide-income country with no special regime for newcomers. e-Residency lets you run an Estonian company remotely, but it is not residence and not tax residence, so a UK-resident founder with an Estonian company is usually still taxed in the UK and the company may be treated as UK-managed.