Aseprite - Aseprite is an art program dedicated to the creation of pixel art.
IcoFX - IcoFX is an all-in-one solution for icon creation, extraction and editing.
Grafx2 - GrafX2 is a bitmap paint program inspired by the Amiga programs Deluxe Paint and Brilliance.
IconWorkshop - Application to create and manage software icons. A must for developers.
Piskel - Piskel is a website where designers online create sprites or pixel art.
IconLover - Icon editor for Windows.