It took me a while to find nice labels for my sewing projects. I tried using printed labels, and had them done on a place on Etsy. I was so disappointed when they started ripping off the edges, and when they faded.
I started looking for woven labels, and finally found a place. Worldwide Label made me these adorable labels. They were so easy to work with, and have a ton of fonts and colors. The labels are sturdy and strong, and I have a zillion of them and didn't spend that much for them.
As far as my size tags, I bought a ton of them in bulk from Celtic Cloths ages ago. They are woven as well. When we got bigger than XL, I bought a small batch of 2T/ 3T/ 4T to hold me over until I can re-use the XS/ S/ M/ L/ XL again. I got them on Etsy and they are fine. I overpaid for them a bit, so I am not going to recommend them.
But having labels in general is quite satisfying. Size labels are a must when sewing kids' clothing, especially if you plan on saving your items for future progeny. Labeling your items with my tag just makes me smile.