When I think of essential tools, I’ve already mentioned the wheelbarrow and loppers. We could add the Cuisinart in the kitchen. Well, you get the picture.
But let’s not overlook the hammock.
She protested when she unwrapped the hammock we’d landed for her birthday.
Still, it went to the Smoking Garden, set parallel to the barn. And her resistance wore down, bit by bit, till one afternoon she fell asleep in it. She never, I should add, takes a nap. Ahem.
I’d say a hammock is an important garden tool, or thinking tool, even if it has no handles. You can work out a lot of problems there.
At the moment, it’s in pieces, stored in the top of the barn. Like so much else, waiting for warming and thawing.
Jnana's Red Barn 
You’re right about the importance of a hammock. Things do get worked out. What I love is how easy it is to leave life behind while in one which is why my bedroom does not have a bed. I sleep in a hammock.
Ah summer breezes in the hammock after a long day of knocking things off the TO DO list…soon?
I would be lost without my hammock! Definitely one of the most important features of my yard and garden.