dired-garbage-files-regexp

dired-garbage-files-regexp is a variable defined in `dired.el'.
Its value is

"\\(?:\\.\\(?:aux\\|bak\\|dvi\\|log\\|orig\\|rej\\|toc\\)\\)\\'"

Documentation:
Regular expression to match "garbage" files for `dired-flag-garbage-files'.

You can customize this variable.