The first real fantasy game I zeroed in on in the 90's when D&D lost it's sparkle for me was FASA's Earthdawn. Now, a lot can be said about FASA and their...approach to game rules...but with Earthdawn, they hit on some very advanced ideas.
One of which was that limiting powers by "uses per diem" was a very outdated idea. Player characters in Earthdawn all learn to draw upon the magical energies of the world, even Warriors and Archers. For most characters, this takes the form of passive abilities or cool combo moves that can be used round after round (with the more dramatic ones requiring Strain, ie, a small amount of damage, or Karma, a resource that costs xp to replenish).
Spellcasters, however, had a very neat system that actually tied into the setting's lore. The short version is, casting spells right out of one's spellbook was possible, but super dangerous. So you don't do it. Instead, you learn to create a mental construct that you can store a spell in. The amount of these are limited- a starting Wizard, Nethermancer, Illusionist, or Elementalist will have at most 2.
You also have a grimoire that has all the spells you know written in it. You put a spell, like say, Earth Darts, into this "spell matrix"- it's all ready to go, but it needs you put power into it. You can change out what spell is in the spell matrix, but this is usually time consuming- a skilled spellcaster can do it on the fly, but it's difficult.
So generally, in an "encounter", you'd have a few spells ready to go. Simple spells can just be cast as an action on your turn, but their effect is generally weak. More powerful spells require you to make an action to power them up.
An early example of this is, the Wizard might have a simple spell that inflicts damage equal to your Willpower die +2 steps (a step is basically the average result increased by a number- so if your Willpower die is d8, which has an average of 4.5, +2 steps gives you d12 with an average of 6.5. Yes, larger steps add more dice, lol).
The more powerful Earth Darts of the Elementalist does Willpower +6, but takes two actions to cast. 1 to "weave a thread to it", ie, give it power. The second turn, you can cast it. A few spells do have extra requirements, like maybe you need an object that costs some money, or some other esoteric requirement, but this is the gist of the system.
Otherwise, spells can be cast as often as desired or needed- the balance was largely time (and the fact you had to make rolls to cast them). So in a critical scene, where action economy is important, a potent spell might not be worth using, and you are generally limited in what you can cast right now this instant. But yeah, no carefully managing resources- if you have 1 encounter today, 7, or 0, your character doesn't perform any better or worse than normal.