I played the Shattered Star AP, and in the last chapter...
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...you get to use the titular artifact. It give bonuses for bouncing it around the party, so everyone got to play with it. That was pretty fun.


Before that, I remembered playing in a deliberately OTT 27th-level gestalt 3.5 game. My character was relatively tame (for a sorcerer//paladin that was basically a dragon-centaur-theing due to free template shenanigans), but one of the other guys had a sword that did 1d100 con damage on a hit!

Also from that era, I once played a game where the GM wanted us to find a proper dragon's hoard (like in the Hobbit films, although this was before that). We offed this dragons, and there was literally millions of gp - mostly in coins but with a few choice magic items and objet-d'art. The GM figured it was in the middle of nowhere and we could not move it all by ourselves, so we'd have to hire porters, wagons, etc, and word would get out. So we'd only get to keep a portion of it in the end; still a generous haul but not the full amount.

Unfortunately, he had forgotten that we had recently acquired both a castle and a pair of ring gates, and one of the latter was conveniently in the vault of the former. TBF, he went with it, and it made for an interesting dynamic. So not a singular item, but there aren't too many 11th level Wizards with a +6 cloak of charisma!