Rings of Elemental Missles
There are 5 different rings and all the rings increase in power as additional rings are worn. A single ring may be used each turn by the wearer and the missiles require a roll to hit.
Each Ring starts at a base damage of d6 and a range of 60 feet.
Range increases +30 feet per additional Ring of Elemental Missles worn.
Damage for all Rings of Elemental Missles increases +1 die size per additional Ring worn (d8, d10, d12, d20).
Each Ring of Elemental Missles inflicts the following damage type and has the following secondary effects:
Air - Thunder Damage, Knockback 5 feet, save or knocked prone.
Earth - Bludgeoning Damage, Knockback 5 feet, save or knocked prone.
Water - Cold Damage, Knockback 5 feet, save or knocked prone.
Fire - Fire Damage, save or catch fire automatically taking fire damage of the appropriate die size next round.
Lightning - Lightning Damage, save or be stunned for 1 round.
PS - I'm told +15 feet, instead of +30 feet would fit better for 5e. Also maybe replace Stun with Lose your Reactions for 5e. But I'll leave it up to individual DMs to decide.