FFmpeg is a widely used, open-source, and cross-platform software that can encode, decode, transcode, mux, demux, stream, filter, and play various multimedia formats, including Matroska.
MKVToolNix is a collection of tools and libraries that can create, modify, split, join, inspect, and extract Matroska files. It is also open-source and cross-platform, and supports various video, audio, and subtitle formats.
VLC media player is a popular, open-source, and cross-platform media player and converter that can play and edit Matroska files. It has various features and filters that can manipulate the video, audio, and subtitle tracks in Matroska files.
Avidemux is a free and open-source video editing software that can create, edit, and convert Matroska files. It supports various codecs and filters, and has a simple and user-friendly interface.