My trifecta is doable by the Magic Initiate feat: mage hand, minor illusion, sleep. You can avoid and end more encounters with those than you'd believe.
Lots of good spells here that are always on my list, but I'm going to add Fly which I always take when I can get it. Go where you want to go, see what you want to see, skip over terrain obstacles. There are enough monsters that lack both flight and a long range attack that you can sometimes just rise up and have complete immunity to damage while you blast from above. Upcast it and bring your friends along for the ride.