Diablo 4 players are finding rare Mythic Charms after the latest patch
The Grandfather and Starless Skies Charms have both started to drop, and they are really good.
It turns out 
Hellfire Torch might not be the rarest Mythic Charm you can find in Diablo 4 Season 15! Since the patch went live last night, a ton of players have been reporting getting Iconic Mythic Uniques as Mythic Charms. Two of the most common ones seem to be 
Ring of Starless Skies and 
The Grandfather.
There is no official evidence that drop rates for these were increased, since there was literally zero information on that in the Patch Notes for 3.2.3. However, the timing is a bit suspicious when you take into account the fact that before the patch, barely anyone had any of these Mythic Charms. So it is not impossible that they secretly increased the drop rates a little bit.
Still Rare, but We Might Know Where to Farm Them
Of course, you are not going to see a Mythic Charm drop every two seconds. They are still extremely rare. But if you want to try your luck and farm for some, it seems that Baal and War Plan chests are the best spots.
War Plan chests take naturally longer, since you do have to complete War Plans first, and that involves going through 5 different activities.
Baal, on the other hand, is already your best farming place for Charms in general, among materials and other types of loot, so you might want to spend even more time in Worldstone Keep now.
If you manage to get The Grandfather or Ring of Starless Skies, and you combine it with the Double Charm meta around Hellfire Torch and the Seal swap trick, you will get a huge boost for your build.
Baal and War Plans are not guaranteed to be the only places you can obtain Mythic Charms. You might drop some in Helltide or any other place. These are just the two spots where players have reported obtaining one.