Here, why don't I give you all of them:
http://www.giantitp.com/forums/show...stances-Immunities-Vulnerabilities-and-Damage
Of the damage types available to you in your bard an wizard cantrips, fire is resisted the most (though note that it's also strong against the most creatures), followed by cold, lightning, acid, necrotic, and finally psychic.
Damage type does not come into play a WHOLE lot in combat, so as long as you have a LITTLE variety you'll likely never encounter a monster you cannot hurt. It can also be helpful to consider damage types from a utility standpoint; a spell that deals acid damage could be useful if you need to corrode and weaken metal bars, cold spells might enable you to freeze water or other liquids, etc.
And of course, nondamaging spells can be quite versatile if you're clever about them. Never underestimate the value of a well-placed
minor illusion!