The best alternatives to Mars Design Club are Prototypr, UX Overflow, and QritiQ.me. If these 3 options don't work for you, we've listed a few more alternatives below.
UX Designers Club is a UX/UI design publication on Medium. Read helpful tips for your design career growth written by Olha Bahaieva, a lead UX/UI designer. Publication is free to read for all Medium users.