PNG SVG MORE
Social media
Smooth
Icocentre Free Icons
Back, send
Black
508x512
PNG ICO MORE
Handdrawn
Jolly Icons Free – 36 Hand-Drawn UI Icons
inbox, letterhead, hand drawn
64x64
Education & science
Brainy Icons Free — 36 Science and Education Icons
submit, creative, Letter
PNG ICO ICNS SVG MORE
Avatars & smileys
Jolly Icons — Part 1: Social Media and Communication
@, mail, send
512x512
Mixed
Outline
Linecons Free – Vector Icons Pack
Email, send, mail
Tango Icon Library
receive, mail, send
UI
Glyph
Pictype Free Vector Icons
PNG ICO ICNS MORE
Desktop apps
Farm-fresh
send, receive, Email
32x32
Shiny Icon Set
mail, Message, envelope
Business & finance
3D
FRESH Add-on
send, Bill, Email
256x256
PNG MORE
Files & folders
Spirit20
Closed, send, mail
20x20
mail, Closed, send
mail, open, send
Gnome Web Icons
paper, send, planepaper
send, 64, mail
Bunch of Bluish Icons
send, group, Community
send, user
Simplicio
send, mail
128x128
Wireframe mono icons
save, send, download
48x48
Ultimate Gnome
send, Move, right
Computer & hardware
Discovery
Free Applications Icons
Arrow, Raise, rise
24x24
Pixel
Gnome icons
mail, receive, send