I’ve had a look through the Greens policies. Here’s what I reckon they could get National to agree to in exchange for merely abstaining on supply and confidence.
A smart Green Party could probably get all that out of National in return for a simple abstain on supply and confidence. It would be more than they have achieved in the last 18 years. But of course, they’d rather deal with NZ First than National despite the fact they have no negotiating leverage with them.