A tradition of the VM Workshop was the Tools Tape. Attendees contributed mods, original programs, documentation, etc. that they had written that might be of use or interest to other VM installations. Many of the presentations at the Workshop involved these contributions. Tools from a few past Workshops are available here.
VM had a tradition of maintenance in source code which allowed fixes and modifications to nearly all parts of the operating system. The source code was generally licensed to the installations by IBM and user-written code could be freely shared. This enabled a host of valuable developments over the years and many of them eventually became part of the distributed product.