I think of it more as "After you finish making a spellbook, look at this list of spells to see if you forgot about some." someone somewhere listed these categories, and did it better than me, but here you go. A better person would fill in the spells for each category too.
Enchantments negation:(nullify, dispel, harshforge stuff...)
Enchantment negation negation: enchanters wardstone
Equipment negation: dissolve, acid ball, disarm
Equipment negation negation: armor ward
Condition removal: wand of healing, purify, or renewing spring are 95% of them
immobalization/moving enemies:
Anti-immobalization/moving allies:
channelling: mana flower/crystal, discount rings
creature protection:(armor, defenses, aegis, regen, healing, block, ect):
anti-creature protection:(armor reducers, some of the equipment negation again, falcon precision)
Damage source: (strong overlap with anti-creature protection)
and probably some other categories.
Anyway, that generates a list of ~20-30 spells. some categories wont matter every time(like armor reduction in a damage over time book), and some will really matter, like a way to remove mind control or forcefield.
