Good DMs create, great DMs steal.
So what can I steal from BG3?
Weapons:
Unseen Menance has a nice mechanic. You get advantage on attacks ... until you miss. It is 2 rounds by the game; I might make it take an action to regain the feature, just to get rid of bookkeeping.
Club of Hill Giant Strength is hilarious; an inferior weapon with a nice status buff. (I don't like the "set stat to Y" items, but I can replace that with my homebrew effect).
I don't like the conditional bonuses based on the target for weapons. Too much tracking, not enough damage per tabletop second.
A per-encounter (or per-short-rest) maneuver attached to weapons works, as it is something for the Player to track (and is just a checkmark).
Cacophony, which deals +1d4 thunder damage and gives you a 1/short rest smite, is good to steal. I prefer +1dX elemental damage to a +1 weapon, as +X weapon is a bit too effective for its impact.
To that extent, all of the +save DC items and the like are yawn. Mechanically very strong, narratively weak.
Drakethroat Glaive is cute.
Ravenguard's Scorcher, which grants an underpowered maneuver (commander's strike) 1/SR but as a bonus action, is also fun. By changing the action economy of the maneuver it becomes quite good.
Sylvan Scimitar is interesting. It it an otherwise mediocre weapon that gives casting-stat-to-attack.
The Watcher's Guide has True-Strike-on-Miss, which I like; applying an underpowered effect with better action economy is great.
Dancing Breeze -- a finess polearm -- is rather fun. I can imagine a PC picking that up in mid game and building their character around it.
I like the fact that rarer items tend to have more than 1 effect. So greyskull helm has
1. Resistance to Fire (nice)
2. Immune to Critical hits (nice)
3. 1/day hunter's mark (also nice)
One issue I've found with mid-high 5e characters is feeling you are locked to some low-level magic item because you really, really want that specific effect (resistance, or whatever). If high level magic items tended to replicate the lower level item effect with extra fun stuff, it makes eventual upgrading more tempting.
Helmet of Smiting isn't bad. I'd probably remove the condition requirement.
The complex lightning charges/burning/etc I'm not going to steal. Similarly "wet = 2x lightning and cold" is off my table.
I sort of like magical plate reducing incoming damage by a small amount, and definitely throwing in stuff that isn't +X AC. Blackguard's Plate, for example, with +1 AC, wisdom saving throw advantage, and 1 point of damage reduction. But it might be annoying to track: I might make it a block of temporary HP that can be recovered as an action (or when taking a second wind).
The medium armors that allow full dex-to-AC are interesting, like Sharpened Snare Cuirass. They are basically "requires better proficiency high enchantment light armor" however.
I appreciate the pile of magical shields that are less than +1 enchantment yet tempting.
Night Walkers are amazing; mini freedom of movement plus 1/SR misty step.
The battlemage items, like strange conduit (+1d4 psychic damage on weapon attacks when concentrating) are fun, or Band of the Mystic Scoundrel (after hitting a creature, can cast illusion and enchantment spells as a bonus action instead of an action). They encourage and reward weaving between weapons and spells.
Ne'er misser, which is a hand crossbow that does force damage and can cast magic missile, is flavourful, has mechanical impact in the game (as force is amazing against physical objects).
The Reviving Hands, which grants bladeward on a heal and death ward on a revive, is just too good an item. As is blessed mercy (grant 2 turns of bless on a heal).
The items like Hunting Shortbow, which grant advantage against monstrosities on all attacks, are interesting. Attune a ranged weapon, get a boost to your non-ranged weapon attacks - this encourages generalization, which I support.
Corvid Token is fun. Always-on feather fall, and effectively a dire raven wild shape 1/day.
Nyrulina - the trident that deals +1d6 thunder (making the 1d6 versatile weapon a good one) that is returning and explodes for 3d4 damage when thrown, feather fall, movement speed and jumping distance boost. (extra damage) (returning) (aoe when thrown) (movement speed and jump speed) (feather fall) - oh and glows - having a collection of fun properties on Legendary weapons makes them interesting and helps them dominate and replace other items.
The Titanstring Bow, which just adds +str to damage, is an interesting weapon to add. Especially if it doesn't require attunement, it might be tempting for a non-ranged specialized PC to pick it up as their preferred bow.
Weapons that grant pseudo-bless like abilities - Phalar Alive for example - are worth stealing. I might have it trigger on a successful hit optionally instead of it being an action.
...
Elixirs are interesting. On TT, they would effectively act as an extra attunement slot and a consumable item. Knowing a recipie and having an alchemist or the like in the party would be similar to having the magic item, but because they are 1 at a time it avoids some of the crafting-spam issues with making magic items (even consumables).
The recipie to make them could require a unique catalyst as well, which would explain why they aren't everywhere.
The accounting of "how many doses left" and buying ingredients is a bit boring however. It is possible I could have a player who likes that kind of thing.
There is a bit of a power gap.
Giant Size is great. The Strength ones, however, are better.
Bloodlust is insane - the game gives out extra actions a bit too easily.
The extra spell slots are interesting. By now allowing you to spam drink them, they become a perk, and won't break the game.
The one that grants warcaster's advantage on concentration checks is solid.
...
Having potions for utility, like detect thoughts/speak with animals/etc has some attraction. It does reduce having those as class features a bit - it becomes about saving gp for potions.
...
A few of the different features for subclasses also look good. I prefer to make changes upwards; but the variety of barbarian rages is interesting (and gives Bear some competition).
...
I love the idea of legendary spells. They can only be used on a refresh, still take slots. It can add a bunch to the game if there are PCs whose goals include gaining knowledge.
The bit where you can get speak with dead as a built in ability by reading the necro tomb is also fun. Similar to a legendary spell.
...
Anything else?
So what can I steal from BG3?
Weapons:
Unseen Menance has a nice mechanic. You get advantage on attacks ... until you miss. It is 2 rounds by the game; I might make it take an action to regain the feature, just to get rid of bookkeeping.
Club of Hill Giant Strength is hilarious; an inferior weapon with a nice status buff. (I don't like the "set stat to Y" items, but I can replace that with my homebrew effect).
I don't like the conditional bonuses based on the target for weapons. Too much tracking, not enough damage per tabletop second.
A per-encounter (or per-short-rest) maneuver attached to weapons works, as it is something for the Player to track (and is just a checkmark).
Cacophony, which deals +1d4 thunder damage and gives you a 1/short rest smite, is good to steal. I prefer +1dX elemental damage to a +1 weapon, as +X weapon is a bit too effective for its impact.
To that extent, all of the +save DC items and the like are yawn. Mechanically very strong, narratively weak.
Drakethroat Glaive is cute.
Ravenguard's Scorcher, which grants an underpowered maneuver (commander's strike) 1/SR but as a bonus action, is also fun. By changing the action economy of the maneuver it becomes quite good.
Sylvan Scimitar is interesting. It it an otherwise mediocre weapon that gives casting-stat-to-attack.
The Watcher's Guide has True-Strike-on-Miss, which I like; applying an underpowered effect with better action economy is great.
Dancing Breeze -- a finess polearm -- is rather fun. I can imagine a PC picking that up in mid game and building their character around it.
I like the fact that rarer items tend to have more than 1 effect. So greyskull helm has
1. Resistance to Fire (nice)
2. Immune to Critical hits (nice)
3. 1/day hunter's mark (also nice)
One issue I've found with mid-high 5e characters is feeling you are locked to some low-level magic item because you really, really want that specific effect (resistance, or whatever). If high level magic items tended to replicate the lower level item effect with extra fun stuff, it makes eventual upgrading more tempting.
Helmet of Smiting isn't bad. I'd probably remove the condition requirement.
The complex lightning charges/burning/etc I'm not going to steal. Similarly "wet = 2x lightning and cold" is off my table.
I sort of like magical plate reducing incoming damage by a small amount, and definitely throwing in stuff that isn't +X AC. Blackguard's Plate, for example, with +1 AC, wisdom saving throw advantage, and 1 point of damage reduction. But it might be annoying to track: I might make it a block of temporary HP that can be recovered as an action (or when taking a second wind).
The medium armors that allow full dex-to-AC are interesting, like Sharpened Snare Cuirass. They are basically "requires better proficiency high enchantment light armor" however.
I appreciate the pile of magical shields that are less than +1 enchantment yet tempting.
Night Walkers are amazing; mini freedom of movement plus 1/SR misty step.
The battlemage items, like strange conduit (+1d4 psychic damage on weapon attacks when concentrating) are fun, or Band of the Mystic Scoundrel (after hitting a creature, can cast illusion and enchantment spells as a bonus action instead of an action). They encourage and reward weaving between weapons and spells.
Ne'er misser, which is a hand crossbow that does force damage and can cast magic missile, is flavourful, has mechanical impact in the game (as force is amazing against physical objects).
The Reviving Hands, which grants bladeward on a heal and death ward on a revive, is just too good an item. As is blessed mercy (grant 2 turns of bless on a heal).
The items like Hunting Shortbow, which grant advantage against monstrosities on all attacks, are interesting. Attune a ranged weapon, get a boost to your non-ranged weapon attacks - this encourages generalization, which I support.
Corvid Token is fun. Always-on feather fall, and effectively a dire raven wild shape 1/day.
Nyrulina - the trident that deals +1d6 thunder (making the 1d6 versatile weapon a good one) that is returning and explodes for 3d4 damage when thrown, feather fall, movement speed and jumping distance boost. (extra damage) (returning) (aoe when thrown) (movement speed and jump speed) (feather fall) - oh and glows - having a collection of fun properties on Legendary weapons makes them interesting and helps them dominate and replace other items.
The Titanstring Bow, which just adds +str to damage, is an interesting weapon to add. Especially if it doesn't require attunement, it might be tempting for a non-ranged specialized PC to pick it up as their preferred bow.
Weapons that grant pseudo-bless like abilities - Phalar Alive for example - are worth stealing. I might have it trigger on a successful hit optionally instead of it being an action.
...
Elixirs are interesting. On TT, they would effectively act as an extra attunement slot and a consumable item. Knowing a recipie and having an alchemist or the like in the party would be similar to having the magic item, but because they are 1 at a time it avoids some of the crafting-spam issues with making magic items (even consumables).
The recipie to make them could require a unique catalyst as well, which would explain why they aren't everywhere.
The accounting of "how many doses left" and buying ingredients is a bit boring however. It is possible I could have a player who likes that kind of thing.
There is a bit of a power gap.
Giant Size is great. The Strength ones, however, are better.
Bloodlust is insane - the game gives out extra actions a bit too easily.
The extra spell slots are interesting. By now allowing you to spam drink them, they become a perk, and won't break the game.
The one that grants warcaster's advantage on concentration checks is solid.
...
Having potions for utility, like detect thoughts/speak with animals/etc has some attraction. It does reduce having those as class features a bit - it becomes about saving gp for potions.
...
A few of the different features for subclasses also look good. I prefer to make changes upwards; but the variety of barbarian rages is interesting (and gives Bear some competition).
...
I love the idea of legendary spells. They can only be used on a refresh, still take slots. It can add a bunch to the game if there are PCs whose goals include gaining knowledge.
The bit where you can get speak with dead as a built in ability by reading the necro tomb is also fun. Similar to a legendary spell.
...
Anything else?