Any utility spell (feather fall, comprehend languages).
Any damage spell at level 5+ (burning hands, magic missile). Scale them up at 11 (2nd level slot) and 17 (3rd level slot). 5d4+5 magic missile = 17.5, compared to 4d10+20 * .60 eldrich blast = 25.2.
Soft control that takes concentration can be fine (fog cloud, fairy fire).
Concentration buff spells (bless, hex).
Avoid Healing (cure wounds)
Avoid hard control spells, particularly those without concentration (tasha's hidous laughter, command). Sleep would count as a damage spell.
You could probably give plenty of level 2 spells at-will as well following the same advice. Though maybe wait till 11 to give damage spells.
I mean, wizards get any first and second level spell at-will at level 18.