psi-plugins is a small collection of LV2 plugins ideal for (but not limited to) electronic music. It uses the ntk widget library (possibly provided by your distribution as non-ntk-devel/ntk-dev)

super_welle: a 4 oscillator / 16 voice virtual analog unison synthesizer

midi_gate: an enveloped stereo MIDI gate

sidechain_gate: stereo sidechain gate (with hysteresis) based on Steve Harris's Gate plugin