That's a good question. There are a couple of keyboard's which could be considered helpful for typing speeds. The first one that comes to mind is Fleksy keyboard+GIF; when it comes to speed Fleksy is king. Of course, what it makes up for in speed, it lacks in predictions. Then there's Google keyboard; while it might not have the same capacity for raw speed that Fleksy does, it makes up for it with its various other features. For instance, Google keyboard provides its users with a excellent auto-correct; being able to predict two to three jumbled words simultaneously! The positioning of the keys can take some getting used to, but it's nothing a little practice can't fix.