bank: an ‘all useful features’ port of Quicken—ndb(6)-like bank account ledger
changelog.rc: Simple (i.e., crude) ChangeLog script for Plan 9 (patch(1) only)
changelog: Slightly more complex (i.e., more likely to fail) ChangeLog script for Plan 9 (patch(1) only)
issue: issue tracking system based on patch(1)
chem: pic(1) preprocessor for chemical structure diagrams
date-rfc3339.c: RFC 3339-ish version of date(1)
mailmerge: troff(1) and awk(1) mailmerge system