What categories would you divide downtime/non-adventuring spells or spell uses into?

[Coidzor]

So far I've got Economic(which includes creating permanent materials to use to make things as well as Fabricate), Creature Modifying(from Awaken to Mineralize Warrior), Minionmancy(Mostly Animate Dead, but also Dominate Person), general skill buffs for Craft and Profession or that aid with non-adventuring research and information gathering(not really sure of a snappy title for that), and Landscape Alteration(Things like Move Earth or Permanent Alter River (http://www.d20pfsrd.com/magic/all-spells/a/alter-river)), and maybe stuff for pulling off Charlantry, though that last one has a significant amount of overlap with adventuring spells when it comes to social challenges.

In a 3.P or Pathfinder environment, there's also the spells that straight up explicitly interact with the Downtime or Kingdom Building subsystems and any others where the rules were made to try to level the playing field with casters, which is sort of a miscellaneous section unified by where they're able to be applied.

I could also see maybe spells that when made permanent or in certain magic item form would allow for perptual motion machines or magitek or pulling off a pseudo Industrial Revolution as a collection of curiosities and the like.

[GilesTheCleric]

Those are some neat categories. Person_Man's niches might be a good place for inspiration, too. I personally use these categories when evalutating Cleric spells, though they're not limited to downtime spells:

Archer -- best suited to an archer-style gish
Artifice -- beneficial to a character that creates things
BFC -- is a BFC
Blasting -- deals direct damage
Buff -- improves you or your allies
Caster -- best suited to non-weapon using combatants, who use spells from the backline
Cure -- removes negative conditions, heals
Debuff -- inflicts a negative condition on your foe, but isn’t a SoS
Divination -- acquires knowledge, or is a divination
Gish -- best suited to a weapon-using combatant, assumed to be melee
Grapple -- best suited to a grappling build
Holy -- best suited to an undead-hating combatant
Minion -- useful for those with lots of summons/ minions; useful to those minions
Necro -- best suited for necromancers
SoD/ SoL/ SoS -- is a Save or X
Tricky -- most powerful in the hands of clever players
Utility -- useful out of combat, or has a multitude of uses


I generally give most downtime spells the "utility" tag, though of course being more specific about it might be helpful. Rather than trying to determine what all each of them could do, though, you could look at it from a different approach: how they let you interact with the world, in a more tier-style approach. Eg. overcomes challenges, provides bonuses to challenges, obviates challenges, or creates challenges. Each of these could also probably be classified with a directly/ indirectly modifier, but I don't know if that's really necessary. Maybe RP could be an additional category that's a bit different to "creates challenges".

[Naez]

Wait you mean you can use downtime to cast spells besides explosive runes?

[Deophaun]

Wait you mean you can use downtime to cast spells besides explosive runes?
Sure can! Empowered explosive runes, maximized explosive runes, transdimensional explosive runes, fell drain explosive runes, snowcasted energy admixture explosive runes...

[Coidzor]

I must admit, I'm not sure how exactly to categorize Explosive Runes. A trap spell? Pre-Adventure prep?

The Niche System is something I had completely forgotten about, might make for an interesting dimension, thank you.

[Deophaun]

I think that's a problem with a system of file categories: you must pick one and only one. Tags, on the other hand, let you stick as many labels as are appropriate.

[Zanos]

Security might be a good category. Hallow, Forbiddance, Guards and Wards, Symbol of X, and the like. Certainly not combat spells with their cast times. Explosive runes is met to fit into that category, I think. Stacking it a million times then using it in combat came later.

[GilesTheCleric]

I must admit, I'm not sure how exactly to categorize Explosive Runes. A trap spell? Pre-Adventure prep?

I tagged Zap Trap (the Cleric's cantrip version of explosive runes) as [Blasting, Artifice], and the Glyph line as [Buff, Debuff, Blasting, Artifice] under my system. Then again, Stalactite Trap is [Utility, Blasting, Tricky], but it has a little more versatility (relatively) than Zap Trap.

I don't know if pre-adventure prep is a useful label if you're only looking at spells that you'd use during pre-adventure prep. Trap does seem like a good moniker, and then you could add some other descriptors to it, perhaps based on what kind of trap it is (blasting, BFC, action-economy-negating, SoX, etc).

[Deepbluediver]

I mostly try to look at spells that are good in combat and/or would be useful on a daily to weekly basis for an adventuring party, and everything else. For example, a spell to create a permanent transportation circle isn't much use to a nomadic group unless they visit the same places a lot or have a home-base to come back to.

For this reason (and others) I redid how some magic items worked. Since we already have wands and potions, I decided that a "magic scroll" is NOT just another storage medium but is linked to a special class of spell that can't normally be learned but can be cast by anyone with sufficient magical mojo and the knowledge to decipher the scroll, with the scroll acting as a combination instruction manual and magical focus. That way casters don't have to worry about wasting spell slots on niche spells, and it's easier to control when and how some of the more gamebreaking or cheesy magical conveniences enter into a campaign.