The D&D 3e Forgotten Realms Campaign Setting places its base year at 1372 DR. Someone once told me that, at a point between this and the year of the current D&D 5e products, a sundering of the Spellweave killed off the wizards of Toril en masse.
Did any wizards survive this event, and do any wizards alive in 1372 DR survive to the "current" (D&D 5e) era?
Besides "ageless" characters like Elminster, Halaster Blackcloak (Mad Mage of Undermountain), Trobriand the Metal Mage (whose spirit is in an iron golem), Laeral Silverhand (the Open Lord of Waterdeep), Szass Tam (Red Wizard lich lord), Manshoon, Malchor Harpell, etc. and other iconic characters like Volothamp Geddarm (trapped by an imprisonment spell and released after a century), we can safely presume that very many Halruaan wizards must have survived, as Halruaa could foresee the upcoming turmoil and managed to disappear from the surface of Toril before the Spellplague struck. Furthermore, we can expect to encounter elven wizards from Evermeet, a century being not such a long time period in their lifetimes, and the island simply having been pushed into the Feywild by the Spellplague.
It is also quite conceivable that some "heroes" of the very many FR tables from all around the world are still around. High-level wizards can have clones, can stay in stasis, can achieve undead status, can travel to the planes, can travel in time etc. to survive.
Volothamp Geddarm appears in multiple published adventures in the 5e line. His mentor Elminster is mentioned in source books, and stars in novels from the same period. Both are very, very old. I'd wager that "someone" was mistaken and that nothing of the sort happened. In either case, there are at least 2 that are still alive.
I think you are talking about the Spellplague which started in 1385 DR. A lot of wizards did die or go insane but some survived and had to learn how the new rules of magic worked. As Derek's answer says, Elminster is certainly still alive (he is likely too iconic to be killed off) and other wizards survived.
