Ashen Rod

"This focus is a rod cut from a tree infused with extra-planar energy, once given in favour by an Ash Baron of the fire plane." 

When you cast a spell that deals fire damage using this item as your spellcasting focus, you gain a +1 bonus to spell attack rolls and to the saving throw DC of the spell.

If the spell is a cantrip, you may also reroll one damage die if you roll a 1. 

Notes: Druid, Sorcerer, Wizard or Warlock, Combat, Focus