You can use either declare or typeset to list function definitions:

1. To list all function names:
   

   declare -F
   

   
   
2. To display a function definition:
   

   $ declare -f quote
   quote () 
   { 
       echo \'${1//\'/\'\\\'\'}\'
   }
   

   
   

If you see a lot of functions with names starting with the underscore (_) and wonder where they come from, they are created by the scripts in /etc/bash_completion.d/.