This is not a mod.
This .zip contains 51 jpegs, each jpeg contains 100 icons.
They are ordered from left to right, top to bottom. Top left is 0 or 100 or 4100, bottom right is 99 or 199 or 4199.
Once you find the icon you want:
offset = column + row*10 + filenum*100
Columns and rows start on 0, not 1.
Spells00-Spells09 are spell icons
Items00-Items40 are item icons
See this post
regarding what to do with them.
I am uploading as addons the hotkey files I used in game to get these and the python script I used to make those files.