Craft holy water is a ritual which every paladin and cleric always has prepared. No, really:
A cleric or paladin may create holy water by performing a special ritual. The ritual takes 1 hour to perform, uses 25 gp worth of powdered silver, and requires the caster to expend a 1st-level spell slot.
That’s kind of great. You can expand the powers of your classes in the mundane equipment gear chapter, I guess implicitly by talking about crafting.
And holy water is pretty magical stuff: it can determine creature types, it washes off a vrock‘s spores, it’s a material component for very useful spells like bless. It’s at least comparable to a single casting of a low-level-character’s cantrip (longer range and slightly more damage of better types than poison spray, but it’s also creature type restricted and is an improvised weapon i.e. raw dexterity attack so less likely to hit, but it ALSO also isn’t subject to magic resistance).
So: I think, per the rules, we can safely transform any cantrip into a one use item at about 25 gp, a spell slot, and an hour of an appropriate character’s time.
Unambiguously (in my opinion 😉 ), we get to add a sort of one use taser, the shocking glass (a jar of bottled lightning, dealing 1d8 damage and denying reactions? Neat!). We also get armor-piercing rounds in the form of the eldritch blast arrow (d10 force damage as a ranged attack at whatever range it’s fired from?) — why spring for these over, say, silvered? Because these can damage incorporeals and golems. Ouch.
The glue of mending is similarly an item that seems very reasonable; at least it can do what it says on the tin. The spare the dying stimpak doesn’t seem quite worth it to me against the potion of healing + getting the injured out under their own motion (or a regular healer’s kit!), but maybe there’s some externality there that makes it worth it. The potion of healing doesn’t talk about its manufacture, but it seems to me like it must have very similar text to the holy water given its ubiquity (a caster of any type, an hour, the list price; maybe a 3rd level spell, but on the other hand, maybe not!).
We get a host of performance enhacing drugs. Of particular interest to me are the potion of true strike and the oil of blade ward, since the cantrips aren’t generally worth learning, but I could imagine corner cases where you’d still want the effects. The straightforward potion of resistance and potion of guidance are nice, and lead to the bard crying in the corner. Does 25gp make this kind of portable bonus a reasonable tradeoff? I’m not really sure; true strike is not so different from hidden; resistance and guidance are more open questions.
The philtre of friends is kind of funny-slash-laughably-bad; it’s surely the philtre of love that’s within reach of the common man, but since its duration is only 1 minute long, you really have to get moving. It is a little sad there isn’t a “peasant scale” love charm/curse because of their role in fiction, but then, D&D’s world is at an interesting point on the High Magic curve anyway. Most stories with a tinge of the supernatural have a couple REALLY GOOD items, because they only need to last for one story. Put a REALLY GOOD love potion in the game at 25gp and the world’s gonna end.
Then, finally, we have the nasty pamphlet of vicious mockery, a satirical little weaponized pamphlet made illegal in twelve boroughs.