Readwise - Effortlessly rediscover and organize your Kindle highlights
LinkedIn Learning - Online training through LinkedIn's professional network.
Newsletters to Kindle - Read your newsletters on your Kindle
Hackr.io - There are tons of online programming courses and tutorials, but it's never easy to find the best one. Try Hackr.io to find the best online courses submitted & voted by the programming community.
Knotes - An efficient, beautiful Kindle highlights & notes manager
Fluany - Everything you need to force your mind to learn