What tasks do you want to do? What sort of garden do you have?

I have large perennials beds and vegetable garden. I do lots of hole-digging -- planting/transplanting of things, including shrubs, so definitely need an ergonomic shovel, and also use a trowel a lot for planting seedlings and smaller plants. Pruners, of course. I don't do too much raking, and I tend to hand-pull weeds unless they're deeply rooted and need a good shovel-loosening first (e.g. dandelions, wild carrots, etc). I hate short-handled shovels BTW -- if that makes a difference.

I have significant arthritis in my hands and have had for many years. Other than making sure that my hand tools have soft grips, the only specifically ergonomic tools I rely on are my Felco pruners with the rotating handle (#7).

Otherwise I use the same gardening tools I have had for years.

How about a proper, light weight, stainless steel, border spade for digging rather than a shovel? And a border fork for loosening. You get a D or T handle rather than having to grip a plain pole, stainless steel cuts through the soil more easily and you can get a good purchase with your foot. Your legs do most of the work rather than your arms and your hands just guide rather than gripping. And by using a fork you are literally just loosening and not lifting any weight of soil. To be honest, I've never understood how anyone gardens using a shovel. 😉 For pruning anything thicker than your finger try loppers. Two handed and long levers.

I tossed using a trowel many years ago, instead substituting a linoleum knife as a seedling transplanting tool, down on-the-knees-weeding tool and general all purpose useful gardening friend. Eliminates the shoulder pressure that a trowel requires. Just a waning that a newly purchased one is very, very sharp and should be handled with care until dulled by dragging through soil. Especially a very useful, precise gardening tool for box gardeners.

For digging up big plants or shrubs, or dividing perennials including large clumps of grasses, nothing beats the Root Slayer shovel IMO. I dug out an enormous clump of Miscanthus and a 6' ninebark all by my lonesome self. With a regular spade I could not even get it into the ground near the grass.