…
..
abbrev
base64
bigdecimal
bigmath
cgi
coverage
csv
date
datetime
delegate
digest
drb
English
erb
etc
expect
fiber
fiddle/handle
find
getoptlong
io-wait
ipaddr
logger
matrix
mkmf
monitor
net
objectspace
observer
open3
openssl
openstruct
optionparser
pathname
pp
prime
rbconfig
readline
resolv
rexml
ripper
rubygems/gem
securerandom
set
shellwords
singleton
socket
stringio
stringscanner
syslog
tempfile
thread
time
timeout
tmpdir/dir
uri
weakref
win32ole
yaml
zlib