So I was bored today so I decided to make an Excel file that calculates the damage a spell or auto attack will do based on your characters stats. Currently it works for most spells, except for those whose damage is based upon weird things (enemies hp, your mana, etc.). There is also a second sheet which has auto-attack damage and a 3rd sheet made specifically for Parrrley.
On both of the first two sheets there is calculations for the increased damage per 1 of each stat, as well as a place to input two different items and it shows the damage gained and the damage gained/gold efficiency of that item.
Currently the only calculations you have to do is adding up individual stats (aka you need to know your total damage and total crit chance etc.).
Hopefully this will be useful to someone, if you have any questions or ways i can improve it let me know.