I’m afraid to say you did not reinvent the wheel, your list is a very well known list already, apart from “7 Scythe” never seen that one before. I usually use an Axe for my 7 similar to your shape for 7. But I’ve also studied the rest of the number shape images from 10 - 100 as well which I recommend if you haven’t already studied these. I learned this from Ron White, 10 for fingers (we have 10 fingers), 11 for cricket sticks, 12 for whale, 13 pregnant woman, 14 flower (valentines day), 15 for man in a disable chair etc. I copied some of the other people that made sense to me as well and created some of myself to reach 100 number shapes, in this case 100 would be “Loo” (a toilet). I use this sometimes to memorise phone numbers and number plates of cars, works well, I’m still thinking of other uses for them like memorising playing cards but Dominic system is the one I use at the moment.