We've covered this is subject in a lot of threads over the years. Most have drifted into obscurity, and can only be found through searches. But I'll play along.
My primary area of interest is in video tools, so I'll contribute a few to consider, and why they should be highlighted.
BD Rebuilder: The only free program that can compress unencrypted Blu-ray to smaller sizes and retain the original menus. It has no peers in this particular task. BD Rebuilder can handle both 2D and 3D Blu-ray. It also excels in conversion of Blu-ray to DVD-video.
DVD Rebuilder: An easy to use GUI to compress DVD-video to smaller sizes. It too can retain original menus. The free version works well for most, and since it uses the HC encoder, its output annihilates any results from a program that uses a transcoder (like CloneDVD or DVDShrink).
MakeMKV: The only free Blu-ray decryption program that is available world-wide (free while in beta, but has been in beta status for many years now). It can convert to mkv or keep the entire Blu-ray structure. Also handy for DVD-video decryption and conversion to mkv file format without re-encoding or compression.
VidCoder: This tool is used to convert various types of video input to H264 mkv or mp4. Though based on Handbrake, it offers more options. VidCoder can produce excellent quality for any type of device you want to play movies on, from phones to tablets to big screen tv's. It's results make commercial converters superfluous.
ImgBurn: The best burning program around. It can be used by advanced users or beginners. It will place the layer break correctly in DL DVD media when other burning programs might fail. And it is bulletproof for Blu-ray burns as well.
AviDemux: For simple cuts and joins of video files, this is a very handy tool. Not my favorite for conversion, but it is able to adjust audio/video sync when you run into a troublesome video.
AVStoDVD: This program is used for conversion to DVD-video from many different types of video. Though DVD-video has become less important over the past few years, it is still a viable format for many, and this program is easily the best of the free options for this particular conversion. It can make menus, which is handy for compilations of several videos into one DVD.