Shadeless materials in Cycles

To make any mate­r­i­al shade­less in Cycles you sim­ply need to use an emis­sion shad­er with a strength of 1.0. You can plug tex­tures and any­thing you want, but the final shad­er (con­nect­ed to the out­put) needs to be the emis­sion shader.

The fun part of shade­less is that you don’t real­ly need light rays bounc­ing around. If you’re cre­at­ing an entire­ly shade­less scene (like a 2D ani­ma­tion) you can set all light path set­tings to 1 and the sam­ples as low as 20. Less sam­ples won’t give you less qual­i­ty but you will start see­ing alias­ing. Though it might be use­ful if you’re going for a 8‑bit look.

For even more per­for­mance you can ren­der with the GPU and set the tile size to the entire ren­der size.