Monks, paladins, artificers, and rogues and every single class that can cast 9th level spells.
You realize I mentioned that later? You're just looking silly because you stopped reading.
But the higher level spells are huge.
Wizard higher level spells are huge. They're huge at every level. It's a dumb spell list.
Bard starts with or can get enough wizard spells to be huge.
Sorcerers are good-ish, but that's mainly because their spell list is just wizard with a bunch of unique utility removed. Nevermind that you stop adding more new spells at level 15, meaning all but one of your 8th and
all of your 9th level spells come at the cost of lower level spells known. Still, they get teleport and wish, so they're wizard enough. Sorcerers are not great at it, but they can generally still do it.
Druid higher level spells are decent, but druid low level spells are really uneven, and the class has a general problem with far to many concentration spells. Much like how ranger is grossly overloaded on bonus actions, druids are overloaded on concentration. The fact that wild shape blocks spellcasting for basically the whole game just exacerbates the problem. The game still doesn't do a great job with polymorph effects. The class seems to have levels with a billion good spells and then those with nothing worthwhile.
Cleric higher level spells are mostly garbage, while cleric lower level spells are pretty good. I genuinely found it difficult to pick a 7th, 8th, or 9th level spell for a cleric from just the PHB. Tasha's makes it better, but the spells are mostly
very narrow, which is the general problem with the class's spell list. Yeah, sure, gate is totally busted. It also gets really boring almost immediately.
Warlocks don't have as good a spell list as wizard or sorcerer. But it doesn't really matter that much if they did, because they never stop being wands of eldritch blast. The rest of their spellcasting is simply too shallow. They get so little
of anything between 2nd and 11th level -- which is 90% of the game -- that the class is pretty universally known almost exclusively for it's multiclassing potential. Worse, they don't get teleport or wish with mystic arcanum. Don't get me wrong, higher level spells are still better than what non-casters get, and I said as much. However, my experience is that the effectiveness of casters is mainly in pumping out 3rd, 4th, and 5th level spell effects while burning 1st, 2nd, or 3rd level slots on reactions for defense. Warlock can't do any of that. That's why nobody stick around.).
And honestly rogues don't have much of one after level 11 (while the fighter third attack at level 11 is pretty good.
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And I don't consider blindsense, slippery mind, and elusive to be all that for the rogue.
My experience is that those abilities are more relevant when you get them that they would be if you'd gotten them 7 levels earlier. They're good because they're all abilities that are more useful at high level. The fact that sneak attack keeps scaling basically for free makes the class more than worthwhile.