BS”D
Add to those who really contributed real niggunim:
R’ Chaim Banet
R’ Boruch Chait
R’ Baruch Levine
The Belz baalei menagen – I forget who among R’ Yermiya Damen, R’ Yosef Tzvi Breier and the Kalish brothers are the actual composers.
Reb Michel Twerski (Milwaukee) – a couple of niggunim that we think are of unknown origin or that have been co-opted by Chabad and others are really his work – Hoshia es Amecho and To Love A Fellow Jew (Karev Yoim).
A handful of new Chassidish composers including “Pinky” Weber, Meshulim Greenberger and a couple of others.