This page contains information about magical charms in Diablo 2: Resurrected.
Charms are magical trinkets which impart passive bonuses to a character so long as they remain in said character’s inventory. The charm must be kept in the character’s active inventory - charms in the Horadric Cube or in the stash will not grant the player any bonuses.
Charms come in three sizes: small, large and grand, which take up 1x1, 2x1 and 3x1 inventory spaces, respectively. Like other magical items, charms spawn with a random prefix and suffix that determines the bonuses they grant, and while charms don’t have stat requirements, their modifiers may come with level requirements. The magical modifiers on charms don’t have quite the same range as other items, but they can still impart useful bonuses, like Damage (physical and elemental), Attack Rating, Stamina, Life, Mana, Strength, Dexterity, Resistances, Hit Recovery, Run Walk Speed, Magic Find and, in the case of Grand Charms, +Skills (by tree).
Perhaps the most interesting thing about charms is the fact that they’re basically free magical modifiers not attached to any piece of equipment, making them highly transferable between disparate builds. Also noteworthy is the fact that useful charms can start dropping very early in the game - before you’ve cleared Act 1 Normal difficulty, in fact. Early-game charms might not be the best, but a +7% resistance small charm is something a character can make good use of for an awfully long time.
Only taking up one inventory slot, Small Charms allow for significant stat fine-tuning with minimal inventory commitment. The most sought after Small Charms are ones with the “Fine” property (increases damage and Attack Rating), preferably if it has the “of Vita” suffix (adds up to +20 Life), ones that add +10% - +11% to a single resistance (or better yet, “Shimmering” Small Charms that add +4% - +5% to all resistances) or grant Magic Find (up to +7% Magic Find on a Small Charm). As far as modifiers added vs inventory size ratios go, Small Charms are the best of the bunch.
The least prized of charms, Large Charms take up two inventory slots and provide similar bonuses to Small Charms. While their modifiers can reach higher values than Small Charms, two good Small Charms will usually provide more benefit for the same inventory commitment than a single Large Charge will.
The biggest of the charms, Grand Charms consume three inventory slots, and can have higher modifiers than small and large charms. Like with Large Charms, you’re almost always going to be better off with multiple Small Charms (although +30% resistance Grand Charms are more or less on par with what three Small Charms can provide), but Grand Charms have one redeeming feature that Large Charms do not: they can spawn with +Skills. These valuable modifiers can start spawning around midway through Nightmare difficulty, and give a +1 bonus to a single skill tree. Not all skill trees are equally valuable, of course, so the utility of a +Skills Grand Charm will vary depending on what skill tree it boosts and any secondary mods on the charm. +Skills Grand Charms that add to Life (especially ones with the “of Vita” mod, which can reach +40 Life on a single charm) are especially prized.