Modern chemistries don’t really do 1.5V (nominals are usually above 3V), so you need to package a buck and a boost converter alongside your cell(s). There are li-ion and LFP batteries in alkaline formats but they’re hardly going to be ideal, you’re probably better off going with 18650.
On the other hand, it's quite rare that a tool takes a single 1.5V cell. Many of them will take 2 or 4, and then you can make a double form factor 3V cell that will fit in most double AA holders.
I've also seen manufacturers who make 3V or 3.2V cells in AA format, and then supply a dummy AA-shaped link with it, which is just a straight-through connection like a wire. Put one cell and one link in your tool, or two cells and two links.
