Is there anything comparable to the IPIP for IO psychology, work psychology and the like? The International Personality Item Pool is a public domain collection of over 3000 items and 250 scales. 

Is there anything comparable for work psychology and the like?
I'm not aware of any such initiatives. But it would be great to see.

In general, I think I/O psychology has been a bit less proactive in engaging with the open science approach than some disciplines of psychology. More generally, many researchers are silent on the issue of licences for their scales. Thus, it can be ambiguous about what you are allowed to do with a scale, say, that you find in a published journal article. Furthermore, many scales in organisational psychology are explicitly free to use for research purposes are not free for commercial purposes.