That's a good question, especially for someone who has access to so many wonderful garden tools.
Hmmm...I guess would pick a spade, fork and a long handle weeder. These three tools do the most work in least amount of time. As with with all gardening, it all starts with the soil and the spade allows turn and move large amounts of soil, the fork also is great for loosening and aerating the soil as well as harvesting root vegetables and I don't care what island you're on, you're going to have weeds and plenty of them, so I want a long handle weeder to take care of them. I have built-in hand tools to do the dirty work once the soil is workable.
1) My pokey stick, aka asparagus knife. I use it for so many things, primarily weeding.
2) My steppy stool. I use a one step rubbermaid with a kneeling pad duck taped to it. I drag it all over the place and it is just the right height for weeding. I also have a pricey Tractor Scoot but my steppy stool wins by a long shot. I'm on about the fifth generation as the plastic does degrade.
3) My toolbag, if I am allowed to count that as a tool. I drag it along with my steppy stool and no matter what I need I have it. My tool garage can be 400 feet from where I am working and having everything I need with me at all times save me a ton of trips back to the house. I have pruners, a small lopper, weed killer, rooting hormone, a knife, a scissor, twine, wire, velcro plant ties, water, a cell phone, a pad and pen, a hand rake, hand weeders, folding saw, and so on.
My pokey stick.
A hand shuffle hoe.
For me...pruners, my hula hoe (I think that's what it's called...it's great for running through my gravel "lawn" and cutting off weeds), and a trowel that has sort of serrated edges for digging down into hard clay soil. Regular old trowels with the smooth sides don't work in my soil (I've bent the handles on quite a few trying to dig holes during the summer when the soil is hard) but the one I have works great--I don't know the brand unfortunately, but it's got an orange handle and triangular teeth all down the sides.
My small shovel
My small trowel with sharp edges on one side... (it digs holes for planting small bedding plants and has a sharp side for cutting away roots nearby)
And my water hose with the 10 dial setting function for different type of spray functions
I call it my "Cadillac" straight edge shovel--stainless steel, heavy won't rust and great for digging and lifting (handle never bends).
Don't know the brand, but red handled sturdy pruners.
Ratchet pruners for larger branches...