Denny bought all that stuff a year or so ago so he could be a kite hospital at the Perry Farm's festival. What a nice guy. He bought the most common sport kite spars and connectors.
For personal use, I don't there really is a standard set. It depends on what you are going to build or what you already have.
For making SLKs there are lot of different rods that are being used and the endcaps and connectors have to match the rods.
As for Rev spare parts, the thing that happens on Revs sometimes is the bungee breaks or comes out of the sail. I haven't ever lost the endcap doing that, just the little washer from the back. But to be safe, for a Rev spare part kite, I would carry a couple Rev brand endcaps or check out the alternatives:
fitting to hide the knot (from Kitebuilder.com)
--same as rev from Hang-em High
Add some bungee from either of the above or from a local Army Surplus or camping store.
And the washers. Rev has used many different kinds of washers over the years. For quite a while they used faucet washers.
I buy mine at Lowes. They are size #0, and come in a pack of 10 for 99 cents.