I needed some replacement grips for a pair of pliers that I found, turning to rust in my garden. I cleaned them up in white vinegar, but the handles were split and beyond repair.
I made these and printed them in TPU, I don't recommend PLA as they may not fit and will not be as strong.
I've been playing with TPU filament recently and it seems almost indestructable.
I printed at 200 degeess hot end, 50 degrees heat bed. 0.2mm layer height. Although the heat bed is probably not needed.
There are 4 versions of the grips, they only differ in width and straight or with spur, if you like a nice wide comfy grip, just print the wider ones.