This list is also available in table form.
addbib apply ar arch asa awk apropos basename bc cal cat chmod chgrp chown clear cmp col colrm comm cp cut date dc deroff dd diction diff dirname dos2unix du echo ed egrep env expand explain expr false fgrep file find fmt fold from ftp grep glob head hostname id id join kill lex ln locate lock look ls m4 machine mail make makewhatis man mimedecode mkdir mkfifo more mv nroff od par paste patch ping pr printenv printf pwd rev rc rm rmdir sed sh shar sleep sort spell split strings stty sum tac tail talk tar tee telnet test time touch tr true tsort tty ul uname unexpand uniq units unix2dos unpar unshar uuencode uudecode wc what whatis which whois xargs yacc yes
And just because we're crazy, here are some classic games, too:
adventure arithmetic atc backgammon banner battlestar bcd bj boggle bs caesar canfield cfscores checkers chess ching cribbage factor fish fortune gomoku grdc hack hangman hunt huntd larn maze mille monop moo morse number phantasia pig pom ppt primes quiz rain random reversi robots rogue sail snake snscore tetris trek ttt words worm worms wumpYou can download the huge current tree in standard gzipped tar format, but be warned: it's about a megabyte right now.