Whenever I hear people talk about animation, it's generally either American animation or Japanese animation and I generally get the feeling that people only look to these two places for animation.
What other countries have a well developed animation industries, and what I should I watch from them?
The real question is not "who make good animation" but "how many good animation they make". Like you say Japanese and American animation are really popular and the reason is the quantity of animated product they make (and some of them are really good product). Many other countries made good animated product but usually are a one time thing (not something you see everyday).
Example: Code Lyoko is a good animated product made in France. But there are not lot's of other France production with the same quality/popularity of Code Lyoko, while everytime Disney make a new movie is almost always popular.
La freccia azzurra known as How the Toys Saved Christmas in the U.S. (by the way, Wikipedia say the US version was cut in same scene, probably because the toys in the italian version do not save Christmas but the "Epiphany" an holiday that in italy for children means the Befana https://en.wikipedia.org/wiki/Befana ) is a really good italian animated movie made by animation studio Lanterna Magica (that also made the most famous Lucky and Zorba in Italian: La gabbianella e il gatto) is a really high quality product but the studio do not produce lot's of things, they just made 3-4 movies and the last one was in 2003. Also, like I said, the US version of the movie is not even complete.
Chinese and Korean animation are already a thing, but since they usually try to replicate anime the quality is still low for most product, except for some really good product like Big Fish & Begonia (also many Japanese product are made or partially made by Korean and Chinese).
There are some really good Russian animated product of tales, like the snow queen story: https://en.wikipedia.org/wiki/The_Snow_Queen_(1957_film)
So the answer is yes, there are lot's of good animated product not made in America or Japan, the only real problem is that are harder to find, not popular like disney movies and usually are a one time thing.
