So I kinda had a dumb idea for a mod, not an overly big one, just a sort of mechanics overhaul

Esentially it would add in an element system to the numerous mobs and entities in the game. Certain weapons would be tied to certain elements, but could be overwritten if desired

The elements:
Light<>Dark
Fire<>Ice
Earth<>Water
Lightning<>Wind
Metal
Aether

By killing certain enemies, you could aquire charges of element they represent, depending on how difficult they are to fight. Now, charges themselves are worthless, unless you have either an elemental catalyst, or empty catalyst equipped. An empty catalyst can be crafted, but when charged with enought of a specific element will turn into that element. Alternatively, you could find and kill a specific boss(vanilla or modded) which embodies said element for a catalyst drop.

With a catalyst equipped, all your attacks and resistances will be attuned more towards it. A flamethrower will do more damage with a fire catalyst, but less with an ice.

Over time as you have a catalyst equipped, it will accumulate more charge, and eventually can be evolved into a stronger version, going Catalyst>Apect>Soul>Prime.

Now, as for Metal and Aether

Metal is a player exclusive element. Esentially if you aren't really interested in doing the whole "resistances" thing. Equipping a Metal catalyst will cause all your attacks to ignore any resistances, esentially turning the game back to vanilla terraria

While Aether is an enemy exclusive element. Any mob not tagged with a specific element will be given the Aether element, not resistant or strong against any other element, but still provides charges when killed.

TL;DR adds element system to mobs, let's player equip items to enhance elements