How do you pick spells to give players on scrolls, wands etc.?
Once you’ve decided "I want to give them a scroll now" or "I think it’s time they deserve to get a spell staff", how do you go about choosing which spells those are?
I assume different people have different ideas here, there isn’t one right answer. This is meant to be an open-ended discussion prompt.
This is adjacent advice but I absolutely love putting 3rd party or homebrew spells in places to be found by players, particularly those who know the available spells on a level up already.
I once dropped this entire spellbook before my wizard where every spell is useful enough to be worth copying down. But a spellbook like this is totally ideal to slip in the one cool spell you want somebody to learn.
As for what spell, players will pick their favourite spells when they level up, so I would just go for interesting spells that have more nieche uses. Spells like floating disk are great for this, but basically any non damaging spell doesn't really ever become irrelevant. I like to put problem solving scrolls ahead of the party like speak with dead or dispel magic, or stamina spells like Jump, Haste or Longstrider. Haste particularly basically slaps at any level, if they're too low of a level, their damage is lower across the board regardless so it doesn't come across as too overpowered, and at high levels, an extra attack is never gonna go to waste.
One of the best items a GM has ever given me was a series of 3 spell scrolls with homebrew spells on them, each of which was encrypted using a different cypher. At the time, but the GM and I were uni students doing a course on security, so it was fitting. One had a riddle, where the answer to the riddle was the key to a Vignere cypher. A second was a series of lines that formed a hexagonal variant of a pigpen cypher (but I forget the precise details).
The third we never actually managed to solve fully. At first it appeared as a bunch of letters in a grid. We learnt that it had a map drawn on it in ink that revealed itself under the letters when the scroll (a physical prop the GM gave me) was heated. A riddle given alongside the puzzle was obviously meant to be used with a transposition cypher on the scrambled letters, but we never worked out exactly how to transpose the letters.
Riddles are a classic part of fantasy RPGs, but far too often they're incredibly dissatisfying or even frustrating because they both require out-of-character solutions and they block your progress in the story until they can be solved. I really loved these scrolls because it tied the solution to the puzzle to something completely separate from the main quest. It still required solving out-of-character, but at least I could take it home with me and work on it in my own time, rather than being distracted at the table with it.
edit: oh :( you deleted your comment while I was writing my reply. I enjoyed your reply. It was a good contribution to the conversation.
I deleted my comment because I came from the TTRPG network homepage and didn't realise I was responding to pathfinder. I gave quite a few D&D 5e specific examples and was a little worried people wouldn't be happy about it.
To be fair, my answer there was also back when we were playing 5e. But I felt ok sharing it here because the general story was system agnostic, dealing with how puzzles with a reward are cooler than puzzles that block story progress, and reinforcing the cool idea you brought up about using custom homebrew spells as reward items.