I often lose track. Ideally I want a command that will list the names of global modules that I have $ npm link'd to local copies, also listing the local path.
In fact, a list of all globally installed modules would be even better, with the npm link'd ones flagged somehow.
Did you try just listing the node_modules directory contents (e.g. ls -l node_modules | grep ^l)? They're normal symlinks.
If you really need to find all symlinks, you could try something like find / -type d -name "node_modules" 2>/dev/null | xargs -I{} find {} -type l -maxdepth 1 | xargs ls -l.