Do you have any recommendations for RPGs built solely around magic using pcs? I've always liked the idea of pure caster parties, and while that's certainly very possible in d&d you can definitely feel that the system was designed with the assumption of more varied and "balanced" parties.
Basically any superhero or urban fantasy game could reasonably be said to be “built solely around magic using PCs”, but since you mentioned pure caster parties, I suspect you’re looking for something in the mode of traditional fantasy, correct?
If that’s the case, you might have a look at Ars Magica. The game’s default assumption is that the player characters will be a coven of Hermetic wizards in Mythic Europe. It has extremely detailed rules for studying magic, inventing spells, crafting magic items, gathering components, and so forth - basically, it’s hyper-focused on Being A Wizard like no other game I’ve ever seen.
One of the major potential pitfalls of this setup is that having a bunch of wizards all running around at once would be very complicated - and thus very slow - to play out. Ars Magica addresses the issue via troupe-based play: every player actually has multiple characters, with the character you play depending on what’s going in in the game.
It works like this. At a minimum, each player creates:
- One magus (wizard), using the full character creation system
- One companion, a powerful non-wizard character who serves as an assistant, bodyguard or other favoured servant of a different player’s wizard (i.e., you do not create your own wizard’s companion), using an abbreviated version of the same character creation rules as wizards
- One or more grogs, minor characters who go into a shared pool, using simplified character creation rules that cut out all the complicated stuff
During “downtime” (i.e., when nobody is out actively adventuring), everybody plays as their wizard in a framework that uses seasons as “turns” (i.e., four turns per year), playing out the study, magical research and feudal politics your wizards have become tied up in.
When actively adventuring, on the other hand, normally just one player’s wizard will be “on screen” at a time (very few situations warrant multiple wizards gallivanting about together), while everybody else plays as their companion character. (i.e., a “party” consists of one wizard and one or more companions.)
You’ll typically want to rotate the spotlight so that everybody gets a chance to have their wizard strut her stuff, though it’s totally acceptable if a given player wants her wizard to stay home all the time and craft magic wands or whatever - that’s 100% supported, and she’ll have plenty of opportunities to get her companion character in trouble while her wizard is busy.
And of course, anyone can grab a grog from the shared pool at any time if neither their wizard nor their companion can plausibly be present in a scene.
In this way, the game strikes a balance between highly detailed handling of wizardly shenanigans, and the danger of having the game grind to a halt if you had to keep track of everyone’s wizardly shenanigans all at once.
A note on content: the game’s Mythic Europe setting is based on the premise that the medieval European worldview is essentially correct, which includes certain assumptions about religion. On the one hand, it provides an amazingly rich body of lore for the game’s magic system, because it’s drawing on real-world Hermetic mysticism; on the other hand, some players might have a problem with playing in a setting in which the God of Abraham is objectively and demonstrably real, even as a fictional conceit. The setting very pointedly refuses to weigh in on which Abrahamic religions are correct - for example, faith-based magic resistance operates identically for adherents of Christianity, Judaism and Islam - but if you prefer a milieu with a D&D-style kitchen sink approach to religion, Ars Magica definitely isn’t that.
You can preview and purchase the game in print and PDF here, though the hardcover version is presently out of stock.