CONV. - Convert YouTube video to MP3, GIF or MP4
Ralpha Image Resizer - High-speed image batch conversion tool
Downie - Video download for OS X. Downie supports at this moment over 1,000 different sites.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Yout - YouTube to Mp3 Converter
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.