A fighter using Booming Blade means not benefiting from its Extra Attacks. It’s nice at low level, but replacing 1 or 2 of your swings with some damage if you hit is situational. See this analysis. There are utility cantrips. For use in combat I’d pick a ranged damage spell and Mind Sliver is only Verbal so no need to free a hand up.
Mad Mage campaign, last night’s goal: walk from Skullport through Undermountain’s caves to River Sargauth’s gondola “service”.
Enter Azrok’s Hold, show papers.
Security is high, a patrol intercepts them, show papers.
Exit the Hold, ask for directions to the River, show papers.
Get ambushed by Azrok’s bugbears, show papers.
There’s a hobgoblin squad ahead with clear signs of a recent skirmish with drows, show papers. Yes, the River is that way, be careful of the drows.
After a bend in the caverns, they have clear line of sight to the River and proceed. Drow ambush.