Resources: There are various mush resources available for softcode.

RhostMUSH: On-line RhostMUSH help facility

Comsystem: AshCOM or AshCOMv2

RhostCODE GitHub Code Repository for RhostMUSH

MailWraps: MUX2/TM3 Wrapper, Brandy Wrapper, Penn Wrapper

Misc : miscellaneous, softcode

Manuals : Not Currently Available

Searches : You can use any search engine and search for 'mushcode' and you'll find a lot of hits.