> I actually just mean DARPA

NASA is the obvious next example. They pay for a lot of esoteric stuff that once made they don't actually end up needing - but having paid the startup costs - end up contributing to other fields.

I think FEMA also does similar things though at a much less parallel (but a higher volume).

Most of the "regulate and promote an industry" (a dumb idea for structuring them but I digress) agencies also do this. The NRC for example does a lot of research on storing and recycling nuclear waste, but also on new nuclear technologies.

And other military agencies aren't worth leaving out. The army core of engineers pushes a lot of contractors to deliver unique solutions that end up getting resold, see the concrete barriers in Iraq.