Fire Spirit Modifying Bracers
I would like to see auction items that when worn tweak a wearer’s fire spirit spell to be of a different elemental base. Have every other aspect of the spell remain the same, just change the elemental base. So ice spirit, water spirit, earth spirit, lightning spirit.
This type of auction item doesn’t overall increase the power of the spell, just the flexibility, and it would give the wearer a relative unique ability.
If you wanted to be fancier you could do something where if multiple of the bracers are used in the same group their powers increase, but I think just changing the elemental base of the spell would be enough to make them highly desirable.
You could also obviously theme their design based on metals, gems, and other materials with inherent elemental properties.