Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Panolapse - Add camera motion to your timelapse videos, deflicker, and combine JPG images into a video file.
Video DownloadHelper - Browser extension to download videos from the Web
FrameByFrame - Stop motion for mac.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
MakeAVI - This is a quick and dirty app that I wrote because I wanted to do some work with creating...
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.