How do I list all available shell builtin commands?

You can use compgen -b from a bash shell to get a list of the shell's builtin commands.

From the terminal type:

help

---

From help help:

Display information about builtin commands.

Alternatively you can display with enable command: (Both @karel's and @steeldriver's answer works fine.)

enable -a | cut -d " " -f 2,3

If any builtin is disabled then it is shown with -n in out put.

Example output:

$ enable -a | cut -d " " -f 2,3
.
:
[
alias
bg
bind
break
builtin
caller
cd
command
compgen
complete
compopt
continue
declare
dirs
disown
echo
enable
eval
exec
exit
export
false
fc
fg
getopts
hash
help
history
jobs
kill
let
local
logout
mapfile
popd
printf
pushd
pwd
read
readarray
readonly
return
set
shift
shopt
source
suspend
test
times
trap
true
type
typeset
ulimit
umask
unalias
unset
wait