I used nothing but plain wooden handles when I first started. Different sizes and diameters, some home-made, others commercially made handles usually removed from other hand tools.
They all gave perfectly good results. But over time I just developed a need, or at least I thought it would suit me better, to use a heavier handle. Something that would absorb the vibration of the hammer during heavier work was needed, a more solid feel was what I was after.
So I gave those Belgian Style Steel handles that NGraver still sells a try. I bought a couple from Ray after seeing them and him at a show in the early 80's. I tried them out there and they seemed right.
They won't serve everyone of course and style, shape , length weight are concerns that everyone differs on.
Don't hesitate to try different styles till one feels just right. Your hand and wrist can get awfully cramped using one that doesn't quite suit you even though you are adapting to it and still putting out good work.
Even with mine, I had altered them some over the years I used them, a couple I shortened (which didn't work as well as expected!), I had wrapped the handle with thin leather in some instances for a more comfortable and bigger grip sometimes, removed that, ect.
I had always left the peened over hammered end in tact on the handle. It's sort of a reminder to me that I've been working at it for a long time.
Choose a hammer the same way. I liked a heavier hammer, never cared for the standard engravers style though I have a couple and have one I made as well trying to find the right 'one'. Tried slimming and otherwise altering the handles of the chasing hammers too, but they never felt quite right.
I settled on what I was using as a bench hammer in my gunsmithing, a Craftsman 2oz ballpeen,,a gift from the Repair Dept at Marlin. Used for all but the most delicate of inlay detail,,then it's one of the lightweight engravers chaser hammers. That Craftsman hammer has been at it since I started this in '71.
With all that,,I recently had to give up the hammer(s) and chisel for an air assisted engraving unit due to some unfortunate accidents and med problems. Not being able to hold the chisel is a bad thing when you're supposed to be an engraver!
I thought I was done totally, but the air tool has allowed me to keep working to this time.
So there are lots of options out there and plenty of price ranges.