This is a video that a lot of people have asked for. I think that there's a lack of good video tutorials so hopefully this helps some people out. There's not really a ton to be said about improvement in typing, as 99% of it is just practice. Ok now here's a ton of links:
Key rollover test: http://gadzikowski.com/nkeyrollover.html
Nitro Type: https://www.nitrotype.com/
Type Racer: https://play.typeracer.com/
10 Fast Fingers: https://10fastfingers.com/
Monkey Type: https://monkeytype.com/
Colemak typists that I mentioned:
Viper: https://www.youtube.com/channel/UCMSF8VUU1hdo-7pKRsBJefQ
Sophie: https://www.youtube.com/channel/UCSM8z16hnO8kWrPU5FOvQBg
Jashe: https://www.youtube.com/channel/UC_8AeIFkslnFSYmbLv--Eww