When I started hand quilting about 20 years ago there were no hand quilting thread available here in Germany and I had to use a Gütermann cotton thread, 50 weight. It worked - but although I used beeswax to prevent it from tangling and fraying I had a lot of problems with it. I could only use short length of it.
It was a great relief for me when hand quilting thread was available in some shops and now I love to use YLI and also other brands.