Depending on your nationality, a lot of countries have flexible tourist visas. For example, Americans can visit Armenia for 6 months, Albania for 12 months, Georgia for 12 months, India for 6 months at a time (up to 10 years), and so on.

In Europe, you also have many countries outside of the Schengen area, meaning that you can do three months in one then hop to another. E.g. spend 3 months in Berlin, then 3 months in Kyiv, then 3 months in Paris, then three months in Belgrade.

As long as you don't need to look for employment locally, it's relatively easy and inexpensive to get a long-term (12 months plus) visa. I enquired with immigration lawyers in three different EU countries where this was possible, and ended up obtaining a three-year visa in a fourth country. I would estimate this cost about 500 EUR.

If you have a lot of money (hundreds of thousands up to millions), you can effectively buy residency in most countries around the world.

Other countries allow border-running to renew your visa, some countries issue longer visa's on arrival, etc, etc.

Mostly, this all depends on your financial means, which country you choose to spend a longer time in, your levels of determination, and the skill of the immigration lawyer you choose.

Talk to other expats who have already stayed long-term in your country of interest. Anybody who has been there for enough time will know their way around the immigration & visa system and people are usually very happy to share what they know.

It can be a huge hassle if you are independently employed, even in a country with lax visa requirements.