This is a good first effort. There are a few things I might have done differently, but the spells within are creative and have their uses.

Brandish - I like this one. Simple, straightforward, good for a "gish" mage who doesn't want to dilute their spell progression with multiclassing. Situational, but cool. I would have made it a Divination instead of an Enchantment.

Coup de Grace - You'll be great for the first few levels. Take out most any CR 0 monster, take out most any CR 1/8 up to 1/2 monster that you or one of your allies wounded (just make sure this isn't your only attack cantrip). I would have scaled this one up... +2 HP for amount affected (5 goes to 7, 9, then 11), and +2 temp HP (2 goes to 4, 6, 8) at levels 5, 11, and 17. It wouldn't be a great choice later in your adventuring career, but that's fine: not everything needs to scale at the same rate.

Dagger of Force - This is strong. Not quite as strong as Shillelagh at levels 1 to 4, but it scales upwards to be quite a good contender if you want a melee cantrip.

Quiglig's Summary Seal - Cool idea for a cantrip. The 1 round duration is a bit disheartening... I might have gone for a 1 minute (concentration) duration, and added an extra object targeted at levels 5, 11, and 17.

Upright - Almost, maybe, too good, but then almost, maybe, not good enough. Doing this as a reaction at a 60-foot range is pretty amazing at low levels, but at higher levels you might have competition for using your reaction with Counterspell and other shenanigans. Obviously, if your allies don't get knocked prone, this never comes up. Situational, but very strong in that situation.

OVERALL: 4 stars. Solid ideas, execution could be a little better, but interesting overall.

I mean, decent effort I guess. Problem is that of the five cantrips available, only one of them (Dagger of Force) really seems like it would be any use at the gaming table.

Coup de Grace uses an action that would be better served by just using any other attack cantrip or even just smacking them with whatever you have to hand, and the 2 Temp HP doesn't scale at all.

Brandish is... If you are super dedicated to using a weapon you don't have proficiency for, it isn't an awful cantrip, but it's beyond situational.

Quiglig's Summary Seal could be useful... if it lasted longer. As it is, since it only lasts for a turn it prevents it from being a more useful utility cantrip, and is instead just a bizarrely situational use of a valuable line on your spell sheet.

Upright is one that is juuuuust on the wrong side of usefulness. Prone can be annoying, and a killer in the right circumstances, but once again you have to balance it against all the other cantrips available.

In conclusion, most of them are bad, one of them is good, maybe worth $0.50, but definitely not worth more.