KDE 4.0 themes
Oxygen transparent: http://linuxmint-art.org/content/show.php/oxygen-transparent?content=127752. An amazing transparent version of the Oxygen KDE 4.0 theme.
Oxygen GTK: http://linuxmint-art.org/content/show.php/Oxygen+Gtk?content=136216. A port of the Oxygen KDE theme to GTK.
Soft metal: http://linuxmint-art.org/content/show.php/Soft+Metal?content=120867. A soft metallic theme for KDE.
Uniq 1.11: http://linuxmint-art.org/content/show.php/uniq?content=112688. Another very nice KDE 4.0 theme.
More nice themes, these are for Gnome
Awesome elegance colors theme for Gnome Shell.
Linux Mint icon themes
Mashup Five: http://linuxmint-art.org/content/show.php/Mashup+Five?content=95717. A gorgeous icon theme for Linux Mint.
Mint KDE icons: http://linuxmint-art.org/content/show.php/Mint+KDE+Icons?content=82179. A complete icon set for Linux Mint KDE.
Linux Metacity themes
Fitts: http://linuxmint-art.org/content/show.php/Fitts?content=139285. A very nice Metacity theme with large buttons.
Nice wallpapers for Linux Mint