Good spells for a multi classed arcane trickster

[braveheart]

My character is using Mat Mercer's Gunslinger class, but at 6 I multiclassed into rogue, for more utility, I'm hitting level 3 rogue and am choosing my spells for arcane trickster, I'm set on my can trips, and am planning to take silent image and disguise self for my illusion/enchantment spells. What I'm unsure of is what I should take for my unrestricted spell. I'm not using find familiar for RP reasons, but I want to take a more utilitarian spell for problem-solving.

Tldr: gunslinger/arcane trickster, need ideas for the unrestricted spell known.

[Quoz]

The classic choice would be shield. Absorb elements is also useful. There aren't many other 1st level spells that you will be happy with for the length of your career, but these are lifesavers.

[Zetakya]

I'm not familiar with the Gunslinger, but Fog Cloud is instant cover, Color Spray is a close range get out of jail, and feather fall and expeditious retreat are good for the whole "leaving now" vibe with AT.

[solidork]

I'd consider Detect Magic, even if you've got someone who usually packs it as a ritual and especially if you don't. Being able to quickly case a room for magical stuff such as traps and loot is a great tool to have available as a rogue. My Warlock has the invocation to cast it at-will and its useful almost every session.