Shardstone
Hero
So I've been thinking about it.Thanks! I'm still mulling it over. I like the shape of it in my mind, but. Don't want to let it become too niche, too ubiquitous, or too cumbersome when actually rendered.
You want a catalog of spells, but don't restrict them by creature type. Instead, they should be inspired by some creatures.
Trollbane -- Study of trolls has taught us the many ways a creature can regenerate. Cast the spell, make a weapon attack as part of the spell, if you hit deal extra damage and turn off regen for 1 min or until a save is passed.
Dragonfall -- Learn to cripple the wings of a dragon and you can cripple the wings of anything. Similar to an already existing spell, but does damage and inflicts some other effects depending on the exact creature type.
Oozeburn -- Killing an ooze is difficult since it has no head or organs. Oozes aren't the only such creatures. Ignite the creature and reduce maximum hit points equal to the damage delt.
Some of these spells overlap, so Oozeburn can work in favor of Trollbane, meaning Oozeburn should be a higher-level spell.
You could eventually have spells for countering Legendary Actions and Resistances at 5th level, etc etc.