How do I list the functions defined in my shell?

Assuming bash shell:

typeset -f

will list the functions.

typeset -F

will list just the function names.

declare -F actually prints declare commands and not only function names:

$ declare -F
declare -f function1
declare -f function2

You can use compgen -A function to print only function names:

$ compgen -A function
function1
function2

declare -F

Function names and definitions may be listed with the -f option to the declare builtin command (see Bash Builtins). The -F option to declare will list the function names only (and optionally the source file and line number).

Bash Reference Manual

declare -F

will give you the names of all functions

type function_name

will give you the source for a particular function