Per Due by Nobis is for 2 Treble Recorders. This piece requires some harmonics and flutter-tonguing.
Dupuy Tren is a modern piece for 3-6 Recorder players.
1/f is written for 5 Instruments but can be performed with a minimum of 3 Instruments.
Force 12 by Russell Garcia, arranged for Recorder Ensemble by Paul Leenhouts.