I suggest these:
test equipment
repair specific (any type of electronics)
as a transverse to the beginners section, I also suggest these:
analog circuits/projects design, troubleshooting, discussion
digital circuits/projects design, troubleshooting, discussion
hybrid circuits/projects design, troubleshooting, discussion
and maybe also:
power supply circuits/projects design, troubleshooting, discussion
Maybe these would be useful, maybe not... I dunno but to me it sounds like a good idea to have them right now.