Three new pipes I've got to suggest as I don't see them in #roadmap and could add new sounds.
**Cymbal **(suggested octave ranks: 1', 1/2', 1/4'):
High pitched mixture stop, adds brilliance and shimmer. (http://www.organstops.org/c/Cymbal.html)
Trombone (suggested octave ranks: 16' and 32'):
Low pitched and powerful chorus reed pipe. Adds depth and clarity to any full assemble. Commonly used as a pedal pitched. Manual pitch uncommon. (http://www.organstops.org/t/Trombone.html)
Tuba (Suggested octave rank: 32')
A brass instrument imitating pedal stop. According to organstops.org, the most powerful organ stop. This chorus reed can be described as a large-scaled Trumpet. (http://organstops.org/t/Tuba.html)