(going down a rabbit hole now. I think that's the right phrase)
There are loads of sites that offer grave digging services or equipment (e.g. [0]) although none mention hoes that I can see. However, I did find more about the use of hoes to actually dig holes (coming back to the original subject): [1]. How could I have forgotten about 'mattocks'.
[0] https://www.equipter.com/equipter-articles/grave-digging-too...
[1] https://grasstrimmerreviews.co.uk/best-digging-hoe-uk/