a2jmidid is daemon for exposing legacy ALSA sequencer applications in JACK MIDI system.
Main goal of this project main is to ease usage of legacy, not
JACK-ified apps, in a JACK MIDI enabled system.
jack_mixer is a GTK+ JACK audio mixer app with a look similar to its hardware counterpart. It has lot of useful features, apart from being able to mix multiple JACK audio streams.
List of application using JACK.