Vectormagic
It is one of the best results you get. Perfectly fit not only the colors, but also the contours and fillings. It is totally free and there is no limit, so we can use it as many times as we want and for free.
Vectorizer.io
Unlike the previous one, Vectorizer.io does not have as many functions, although it is still very efficient. The good thing about this tool compared to others is that we can remove elements of the image. The bad thing is that it does not often treat the fillings as it should.
Vectorization
Again we have a tool that allows us to move from bitmap to vectorized image without respecting colors. It is also possible to access images online and not only local. Otherwise we can not perform any more function: neither edit the contour, nor the colors, nor the background nor anything.