I'm just now getting speed at arpeggios.
For practice you might want to look up some classical music too - there are lots of songs where the left hand of the piano is constantly playing arpegios at a fair speed, sometimes very fast, and also violinists 'sweep' a lot by changing the angle of the bow so it switches strings.
Not only will it help by giving you more stuff to practice, it might give you ideas you can use and apply in your own music!
Good luck.
