Here is my spur/removal saddle, Monkey Beaver 1.0, which is what gets most of my usage. Thinking about trying out the 2.0.... I've also got a TreeMotion S.light with its own set of equipment on it for pruning jobs where I like something lighter and more sporty.
-Silky handsaw with a leather Weaver scabbard since I don't like the one it comes with.
-Non locking biner for sending certain gear up and down.
-Sling for certain rigging situations, mostly hanging a big fir limb on itself when working solo.
-Small bits: pulley, retrieval ball, quickie.
-Sling dedicated for life support as needed, mostly a redirect.
-Steel biner for making throwing a DRT line on a limb above me easier.
-Pouch with a bar wrench, mini-wedge and where I keep my phone/camera.
-Knife for cutting ropes, mostly an emergency thing. Only used like 3 times, and just for cutting old ropes found in trees.
-Small water bottle, which I use daily.
-TransPorter for hanging my chainsaw.
A few of the items seldom get used, but nothing is heavy and I'd rather grab and go rather than spend time adding or removing just a few ounces of gear before and after every climb...