LMMS

Start with a small rhythm or melodic pattern in the piano roll, then arrange copies and variations into a song. Track automation can shape a sound over time instead of repeating an unchanged loop.

The official feature list includes built-in synthesizers, SoundFont support and platform-specific VST options. Check the plugin format you need before moving an existing project; an instrument being available on one system does not establish that a third-party plugin works on every system.