PNG ICO ICNS MORE
UI
Smooth
Ultimate Gnome
receive, send, mail
Linen
256x256
send, Move, right
Black
Computer & hardware
Crystal Project
send, mail
WhiteSmoke
Function icons
mail, Letter, receive
DarkGray
48x48
Mixed
Carpelinx
mail, send, Forward
64x64
send, Letter, mail
Desktop apps
KDE Crystal Diamond
22x22