One of the most comprehensive free virtual music studio options is Linux Multimedia Studio, which supports Windows as well as Linux. LMMS comes with various trackers and filters, and it has plugins for Virtual Studio Technology instruments.
LMMS comes with a number of instrument-creating tools by default, including two triple oscillators and tools that replicate the sound of various computer chips from the 1980s and 1990s. Users looking for less comprehensive options that are easier to use can consider Temper and DarkWave Studio, which feature sequencing tools and VST support as well as recording capabilities. A free option for recording and editing multitrack audio is Audacity, which has advanced editing features, plugin support and a large collection of filters.