Yusuf Oliver Narcin by John Enoch
Traditionally, trombones tended to be part of larger klezmer ensembles, playing middle voice lines. Today, they might also play melodies.
Dan Blacksberg, a Philadelphia-based trombonist, gives workshops on playing the middle voice in klezmer, and has produced lots of resources on this.
Klezmer trombonists in the late 19th and earlier 20th centuries included:
USA Jack Levitt, Sam Spielman
Klezmer trombonists in the later 20th century and today include:
Israel Rachel Lemisch
UK Camilla Saunders, Caroline Hall, Yusuf Oliver Narcin
USA Brian Bender, Dan Blacksberg, David Harris