Monsters are going to be categorized in three dimensions by element. Unique boss mobs don't need this categorization (They'd probably be neutral across the board, because a boss with a weakness is like Alexmdle with a cold drink
), but general enemies like Goblins and Slimes do.
I've three charts laid out with these, categorized in XYZ form for elements. There 232 unique slots in total.
So any generic monster idea, feel free to categorize it by primary, secondary, and tertiary elements; however with only one-way duplicate elements. For example, Fire-fire-ice is fine, but fire-ice-fire or ice-fire-fire would be exactly the same thing, and entirely redundant. You can still 'suggest' these anyway, as I'll ultimately be the one categorizing things, but I don't need fifty bajillion 'dark' or 'light' elementals.