Traversing directories:

recursive-directory-files ( path -- paths )

recursive-directory-entries ( path -- directory-entries )

each-file ( ... path quot: ( ... name -- ... ) -- ... )

each-directory-entry ( path quot: ( ... entry -- ... ) -- )

Finding files by name:

find-file ( path quot: ( ... name -- ... ? ) -- path/f )

find-files ( path quot: ( ... name -- ... ? ) -- paths )

find-file-in-directories ( directories quot: ( ... name -- ... ? ) -- path'/f )

find-files-in-directories ( directories quot: ( ... name -- ... ? ) -- paths/f )

Finding files by extension:

find-files-by-extension ( path extension -- seq )

find-files-by-extensions ( path extensions -- seq )