The Stanford Encyclopedia of Philosophy: https://plato.stanford.edu/
The Internet Encyclopedia of Philosophy: https://www.iep.utm.edu/
The Routledge Encyclopedia of Philosophy: https://www.rep.routledge.com/
A Crash Course in the History of Western Philosophy: https://truthandlifeseeker.wordpress.com/2020/01/07/a-crash-course-in-the-history-of-philosophy/