E Commit - Has not been updated in a while. But holds some good articles and videos
Muscle Mountain - A UK player who mains 4-5 Handsize Characters and has some great viewpoints from is experiences.
Rules Corner - Kevin Broberg takes us through some of the more nuanced rules in UFS in a clear and decisive format.
The UFS Living Game Rules - The closest thing we have to a complete rule document for UFS.
The Attack Line Design Guide - In PDF form for your convenience.