Canada was - and still is - a very popular destination for Dutch emigrants. There are over 1 million Canadians who are Dutch or whose ancestors are Dutch - and that makes Canada one of the biggest destinations for Dutch emigrants ever! From other countries I don't know the exact numbers. I thought that the number of emigrants to the USA from the Netherlands after WW II was about 250,000. To Australia it was much more, I think also some 500,000 - 1 million. Other popular destinations were South Africa - one of the languages spoken there is Afrikaans from early Dutch settlers, long story, once had family there -, New Zealand and even Brasil! There are also few Dutch who don't have family outside the Netherlands.
I myself have family (close family, like an aunt, but also nephews and nieces from my parents) in Austria, Germany, Ireland, the US, Australia and I thought also Canada, and I used to have family in South Africa, but they came back to the Netherlands after they were shocked by the apartheid (this was in the '60s, '70s of the 20th century). Examples: they got a free gun when they bought their house, so they could shoot "black intruders", and they were not allowed to pay their black servant - they were given a black servant - more than the absolute minimum wage. Apartheid, bah