How many types of Buddhism exists in this world?

many times, I stumbled to start to dig something towards teaching of Buddha and at some point want to make focus on Buddhism. During my journey of looking bird eye of view, I passed through Vipassana, Therevada, Zen, Dalai Lama, Tibet, Nepal and Mynmar. Last read bit about Buddhism in Sri Lanka? How Arthur Schopenhauer inspired himself with Budda? Who guided him or how he came to know about terms like enlightenment.?