Elemental Monk

When you use a ki point to do elemental damage of a certain type you can ignore elemental immunity of that type. In the event that you do elemental damage without spending a ki point, you can choose to spend a ki point to use this feat. 

In the event that you roll a 1 on an elemental damage die, you can re-roll to get at least a 2. 

You can take this feat multiple times. Twice to ignore immunity and resistance. Three times to give vulnerability to elemental type. 

You can also take this feat multiple times for different types of elemental damage.