Skincraft is what introduced me to Newgrounds as I just picked up Minecraft: Java edition. I didn't know what I was really doing so I made a pre-made skin, which was really fun and easy.
You can choose to either use pre-made parts for your MC character or hand-draw them yourself with any colour. It's easy to learn, isn't on some sketchy website, and still holds up as well as it did years ago. God, I can't find a single skin creator that has Ctrl + Z, you have to manually erase each pixel.
Also, you can easily submit a skin you made for others to steal.
All around, nothing wrong with it. It's perfect in my book. 5/5