My 2 biggest accessories out of the norm I refuse to hunt without are..

1 A bow hoist. I really like the ones that work like a dog leash. They dont have rope but a flat nylon line that reels up so I no longer have to screw with a rope in the dark. I dont know many times I got the rope tangled on a branch or just basically tied in a knot on its own after I started to pull the bow up. IF you are just getting into it or haven't tried one of these I would highly recommend getting one....best part is they don't cost much $$$

Below is an example but multiple companies make these. I just set up climber put bow on ground and hook this up to top of climber and bow. No more tangles.
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http://www.amazon.com/Pine-Ridge-Archery-Reel-A-Strap-Equipment/dp/B000LH7VH2


2 I also wont hunt without a simple bow holder. I dont know how many times I had the bow on my lap and accident knocked arrow off and it bangs on something or just from me moving around a hair the arrow bangs on stuff and makes noise. You do have to be a little careful not to know the bow out of the holder but Ive never had an issue. It just makes things much easier not having to worry about the bow being secured while glassing or moving around in general. I used the kind that screw into tree but rarely got it to secure where I wanted to have the bow hanging to make for an easy grab.

I also hate shooting with gloves on so I can just put my hands in hand warmer and leave bow in holder. I have a hard time getting my gloved hand thru my wrist sling and dont like to practice with gloves on. So now I just sit warm and happy. Grabbing the cold bow doesnt bother me cause Im only grabbing the bow when Im know I have a good chance for a shot.

I went with this one on my climber.

http://www.amazon.com/Hme-Products-Universally-Mountable-Holder/dp/B000H1K27I/ref=sr_1_3?s=sporting-goods&ie=UTF8&qid=1374091301&sr=1-3&keywords=bow+holder



I know these aren't big secrets but I like to be as comfortable and trouble free while hunting and these to items for under $30 are what I now consider musts for my stands.

Safety line.

grunt tube and "the can"

+1



And +1 to the bow holder as well.  



I also like various hooks and quiver holders that I can screw into the tree.



 

Bracket for my quiver

safety strap
bow holder

A harness attached to that safety line....and you!

Safety harness with self rescue gear.

Bow holder

Whistle (I have a little pealess aluminum tube goes in my jacket or shirt pocket.)

I seriously recognize the value of the safety harness enough to look at those items more along the lines of necessities for treestand hunting.

The strap bow/gun hoist has been a really great accessory. I love how it winds up out of the way.

Totally agree with the bow holder as well. I use two while up there. One is mounted I the stand and the other is attached to the tree.

The quiver holder has also been a great addition.

Range finder

Branch clipper

iKam video recorder

Bushnell trail cam ( got last year's bow kill on film )

Screw-in-the-tree umbrella.  Priceless.  Roll it up and velcro strap it to the bottom of the stand and you'll always have it with you.



Piss bottle.

safety line, calls and antlers depending on the time of year, piss bottle, snickers bars and kit kat bars, pb and fluff sandwiches. Oh yea, my bow, arrows and rangefinder to ensure my distances.

safety line
the can
grunt tube
copenhagen southern blend  

All the safety stuff already mentioned. AND

If hunting with a buddy, two way radios and cell phone

If hunting alone, a cell phone.

Last year my hunting buddy fell from his stand. He was using a huntersafety system vest and tree strap. We don't know what happened but when he slipped the strap around the tree failed. It held long enough to swing him feet down then failed. He broke his ankle with bones sticking out and all the gore.

Because we had radios he was able to contact me and I got to him in about 5 minutes. What a mess. Bleeding was profuse. I stabilized him and had to walk out to the truck to get the cell phone to call 911.

We now carry both so we don't have to leave the other in the woods to make the call.

EBR666

One of the things that has really made my life better in a tree is the Bino strap system This is not the exact one I use, but its close.. Makes glassing 10X easier.. Last few deer I have shot with the bow I have been able to quickly grab my glass and watch the deer run off and see the arrow placement. Last deer I killed I was actually able to watch him run off lay down and bleed out, didnt even need to track him just walked up on him. Had I not watched I would have never found him, he only went 30 yards but had no blood trail what so ever, and its so thick you would have to actually step over a deer to find it.
Another thing I find handy is having a few S biners with you. I use one to hoist my bow and pack. Its more better then dealing with knots with gloves on.

I feel like a moron; what an obvious thing to do! Guess what I will have for the weekend

Plus another one...