One non-combat cantrip to rule them all

[Flashy]

I'm playing a Knowledge Cleric coming up on 10th level and for complicated in game reasons my DM has agreed to let me choose my last cantrip from the entire spell list. I'm already satisfied with my combat performance and so am looking for something with out of combat applications I wouldn't otherwise have access to. My first thought was either Mage Hand or Message, but I'm really interested to see what the playground thinks.

Cantrips I already have:
Sacred Flame
Guidance
Mending
Thaumaturgy
Produce Flame (I took Magic Initiate)
Shillelagh

[Nifft]

Thaumaturgy allows for the most impressive entrances, and story-telling special effects. If you're going to be speaking in public, it's a very good choice.

Guidance is nice for supporting your local skill monkey.

Mending is good if your DM shreds your clothing on a regular basis... which is roughly never, in my experience.

[The1exile]

Minor illusion, without a doubt. I have a warlock with minor illusion and thaumaturgy and it allows for really cool story telling stuff, ways to show people what you' expectations seen, ghost sound, illusory objects etc.

[Belac93]

Minor illusion is the best. In a PbP campaign I'm playing, I stopped 2 enemies from doing anything for an entire round with this spell, while I was underwater. The closest I could do with other spells I have is a 1st level command, as I am level 2. Command would need me to speak, and for the enemies to understand me (and we were fighting manta rays). Great spell for fooling animals, undead, and constructs. Lets you speak without having to actually talk. Great cantrip.
Otherwise, prestidigitation or druidcraft. With thaumaturgy and those two, you have the best three roleplay cantrips in the game.

[Aurthur]

Mending is great against oozes...or, to be more precise, great for your party after they face oozes. :)

[Flashy]

I will totally keep minor illusion in mind! I wasn't thinking about it, and it's a great pick.

[Citan]

I will totally keep minor illusion in mind! I wasn't thinking about it, and it's a great pick.

I plus Minor Illusion, it's great and usable in many situations.

Another one nice (although more situational) is Mold Earth: you can use it to create small places to rest or hide by excavating and replacing earth around you at no cost, use it to display encoded messages for friends and other things.

Finally Mage Hand can also be used in many ways.

Minor Illusion is the most creative though, so if it's what you are looking for... :)

[beckyangelix]

Minor Illusion is my second choice after Mage Hand. I use it more or less constantly. And it's actually a solid shape (i.e: it can pick things up and actually do things). It can actually do a lot of the same things that Minor Illusion can if you get creative with it.

[NNescio]

Minor Illusion is my second choice after Mage Hand. I use it more or less constantly. And it's actually a solid shape (i.e: it can pick things up and actually do things). It can actually do a lot of the same things that Minor Illusion can if you get creative with it.

Eh, Mage Hand can't really slow down groups of pursuers (unlike, say, Minor Illusion caltrops or the like, or my favorite, Minor Illusion bonfire with Conjure Bonfire, even if the lack of heat can be an issue), and doesn't really let you hide within it anyway.

Plus, most of its uses can be duplicated by ritual casting Unseen Servant. Sure, the latter's approach takes some time, but it's more flexible in its uses.

Minor Illusion can even be used in combat. Hide within an illusion, and then lob spells out of it. Preferably by firing your orbital lasers with Sacred Flame. Strictly speaking if you don't actually use attacks (but just spells that are not spell attacks) it doesn't even break stealth, but most DMs would probably have issue with the verbal components.

With spells like Chill Touch you can even attack with advantage without breaking the illusion, 'though you will reveal your position (since it's uniquely among the few spell attacks that don't involve hurling projectiles or rays, so it breaks stealth, but not the illusion. You still get advantage because you're still unseen even if you're not hidden). And well, if any enemy attacks you, they'll break the illusion too.