Regarding Freelance visas, some countries (e.g. Germany [1]) require you to have local clients. So not an option for self-employed/indies. Would be nice to have similar info about countries that doesn't require you to work for someone else. EDIT: 1. https://allaboutberlin.com/guides/how-to-get-a-german-freela... .
Edit: See here https://www.gesetze-im-internet.de/englisch_aufenthg/englisc...
(1) A foreigner may be granted a temporary residence permit for the purpose of self-employment if
1. an economic interest or a regional need applies,
2. the activity is expected to have positive effects on the economy and
3. personal capital on the part of the foreigner or a loan undertaking is available to realise the business idea.