So, if there's not a list of Linux software to support elsewhere, I'd like to start one for consideration.
WINE: To allow easy running of Windows programs on Linux, bringing with it the Microsoft software ecosystem.
Adobe productivity parity: The only software not even close to good enough quality seems to be productivity tools put out by adobe. This is the last area which is lagging in the Linux space. With this, the last big block to Linux for professionals will be gone.