The Monster Fun todo list of commands that should probably be in 1.0:

  at awk basename bc bunzip2 bzcat bzip2 cal cat catv chgrp chmod
  chown chroot chvt cksum cmp comm count cp cpio csplit cut date dd df
  diff dirname dmesg dnsdomainname du echo egrep env expand expr
  false fgrep file find fold freeramdisk ftpd ftpget ftpput fuser
  getconf getty grep gunzip gzip halt hd head help hostname id
  ifconfig iftop init insmod install ioctl ionice join kill
  killall klogd less link ln logger login logname losetup ls lsmod
  lsof man md5sum mdev mkdir mkfifo mknod mkswap mktemp modprobe
  more mount mountpoint mv nc netcat netstat newgrp newfs_msdos 
  nice nl nohup notify od oneit paste patch pathchk pgrep pidof
  ping ping6 pivot_root pkill poweroff printenv printf ps pwd
  readlink reboot renice rm rmdir rmmod route sed seq setsid
  sfdisk sh sha1sum sleep sort split start stat stop stty swapoff
  swapon switch_root sync syslogd tabs tac tail tar taskset tee
  telnet telnetd test time top touch tput tr true truncate tty
  umount uname unexpand uniq unlink unshare uptime usleep uudecode
  uuencode vconfig vi vmstat wc wget which who whoami xargs yes
  zcat

--- Done or pending

The following commands are done:
  bzcat, cal, cat, catv, chroot, chvt, cksum, count, cp, df, dirname, dmesg,
  echo, false, help, link, mkswap, nc, netcat, nice, nohup, oneit, patch, pwd,
  rmdir, seq, setsid, sha1sum, sleep, sort, sync, tee, true, truncate, tty,
  uname, unlink, unshare, wc, which, yes

The following are partial implementations (unfinished):
  mke2fs, md5sum, sed, mdev, bunzip2

Stuff I personally wrote back in BusyBox, more or less ready to port:
  halt, poweroff, reboot, switch_root, nbd-client

Stuff I worked on in the BusyBox days that needs work:
  sed losetup mount umount setuidgid init nbd-client mdev

--- TODO

Low hanging fruit (I have a plan for impelementing these):
  basename, eject, env, head, kill, ln, mkdir, mknod, mktemp, more,
  mountpoint, mv, detach, killall, pidof, ps, realpath, renice, rm,
  strings, sum, swapoff, swapon, time, touch, uniq, bzip2, uptime,
  usleep, watch, watchdog, whoami, xargs, tunctl, mkfifo, readlink,
  split

To be implemented from the SUSv4 spec:
  at, batch, bc, man

shell
  sh bash alias break cd bg

General todo:
  adjtimex, awk, clear, cmp, comm, crontab,
  cut, date, dc, dd, dos2unix, du, find, fold, free, fuser, hdparm, hwclock,
  install, length, less, linux32, linux64, logger, ls, od, ntpdate, readahead,
  readprofile, setarch, start-stop-daemon, stat, stty, sysctl, tail, top,
  tr, unix2dos, vi, who, file

passwd:
  addgroup, adduser, chgrp, chmod, chown, delgroup, deluser, id, last,
  login, logname, passwd, sulogin, su

pending:
  fdisk

compression:
  gunzip, gzip, lzmacat, uncompress, unlzma, unzip, uptime, zcat
  lzcat lzma lzop unlzop lzopcat xz xzcat unxz

init:
  init getty, runlevel

shellish:
  expr, getopt, printenv, printf, test, pushd, popd

obsoleteish:
  ed, fdflush, fdformat, freeramdisk, fsck.minix, makedevs, mkfs.minix, mt,
  pipe_progress, pivot_root, linuxrc, rdate, rx, uuencode, uudecode

funky:
  dumpkmap, loadkmap, logread, dumpleases

network:
  arp arping dig dnsdomainname brctl ifenslave
  ether-wake, hostid, hostname, ipaddr, ipcalc, ifconfig, ifdown, ifup, ip,
  iplink, iproute, iptunnel, nameif, netstat, nslookup, dig, ping, ping6,
  route, telnet, tftp, traceroute, vconfig, zcip

ipv6:
  ping6 traceroute6 ping6

dhcp:
  dhcpcd dhcpd dhcprelay

wget:
  wget curl ftp tftp ftpget ftpput

daemons:
  crond, dnsd, fakeidentd, httpd, inetd, klogd, syslogd, telnetd, dhcpd
  tftpd ftpd

archivers:
  ar, cpio, rpm2cpio, tar, unzip, zip

terminal:
  deallocvt, fbset, loadfont, mesg, openvt, reset, setconsole,
  setkeycodes, setlogcons, vlock

modules:
  insmod, lsmod, modprobe, rmmod, ldconfig, modinfo, depmod

e2fs:
  mke2fs, e2fsck, chattr, tune2fs, lsattr, fsck, gene2fs, e2resize
  mkfs.ext2

fat:
  mkdosfs, mkfs.vfat

regex:
  sed, grep, egrep, fgrep

package management:
  dpkg, dpkg-deb, rpm

stuff:
  diff
  ipcrm, ipcs
  hd hexdump hexedit
  run-parts
  nl

SUSv4 leftovers:
  csplit expand getconf join lp mailx newgrp paste pathchk pax tabs talk tput
  write join newgrp paste pathchk tabs tput expand

Busybox leftovers:
  ntpd whois lpr mkdosfs findfs volname blkid pgrep pkill showkey
  microcom ntpd slattach whois iprule ash hush [ [[ fgconsole
  chrt ionice shutdown groups mkpasswd cryptpw users sha256sum sha512sum fsync
  tac rev flock ttysize resize timeout blockdev lspci lsusb killall5 lpd lpq
  fbsplash script scriptreplay

toolbox leftovers:
  alarm exists getevent getprop iftop ioctl log newfs_msdos notify powerd r
  readtty rotatefb schedtop sendevent setkey setprop smd syren vmstat
  watchprops wipe