#WizardWeek *Advice by Alex Norris about adding new spells*
There’s generally no reason to add new spells to the game, since the Cleric and Wizard lists are already big enough and neither needs more versatility – if you add more spells, you’re essentially handing them even more moves they can pick from when everyone else only has 20.
That said, if you want to do it anyway:
1) don’t give the Wizard/Cleric any spells that replace or replicate stuff that other classes can do. No Knock or Find Traps for example.
2) don’t give the Wizard/Cleric anything that make them good at stuff they’re not good at, i.e. Tenser’s Transformation or Divine Power.
3) remember that every new Cleric spell you add to the game is a spell the Cleric can take straight off the bat, since unlike the Wizard he doesn’t need to put them in his spellbook.
4) remember that every new spell you add to your game is potentially eating into the niche of a class you haven’t added to your game yet (if you get new players or someone dies and wants to come back as something else).
5) I’d generally avoid giving either any more damage spells, since dealing damage is supposed to be the Fighter’s niche, not the casters’.
I agree Tim Franzke the few exceptions I make in my games, is to allow for narative only effects, such as a cleric orison to render a place peaceful or a wizard to paint a building, something cantrip can’t do and isn’t in my opinion something a ritual should be required for.