Here is a list of resources of general mathematical interest. It will be added to in a large manner.
These are resources I strongly recommend.
Lost Math Lessons Someone who comes across interesting math topics that are not taught anymore. For example, they had a post on the higher version of synthetic division
Not related to math, but these are resources that I found helpful in making the website. Note that I have been dabbling in web stuff for many years though it is only a hobby and my proficiency is intermediate (better at the coding, worse at the design! )