Neonchameleon
Legend
Which is why I'm proposing a sorcerer warlock for the rest of themYou can already build a necro-warlock using various supplements. The undeath patron from Van Richten, there is an invocation in Tasha's they gives animate dead, summon undead and shadow are on the warlock list, etc. But the eldritch blasting, two-spell casting doesn't fit the concept of necromancer for everyone. And it still leaves out white/gray necromancy unexplored. Not every necromancer wants to just raise a family in peace, some want to fight the undead.

That said I think there should be a "Universal" school for spells such as Prestidigitation, Unseen Servant, and Mage Armour; these spells aren't actually universal but have enough variants that if you specialise in a school you can use a school based variant.