My wife and I work (not as frequently as we would like to) on a bunch of euphonium-with-piano things. One is a book of Steven Mead stuff. And now we're starting on some of the simpler Rochut exercises since good piano accompaniment is available for them. We also play Christmas tunes for our children and grandchildren (when they can't manage to run away fast enough), Anna Baadsvik's arrangement of "Gabriel's Oboe", and Dave Werden's (Gounod) version of "Ave Maria". There's a lot of stuff that you can have fun with, even if you're building/rebuilding skills.
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)