The value of Ability Score Increases (ASIs) is well understood. Getting a +1 to just about everything your character cares about is a great, and very powerful thing. But in BG3, your primary stat will start at 17, most likely. So after you put one ASI towards it and it's at 19, with a cap of 20 from ASIs, what are you to do? You could split the ASI and improve another stat as well. For some particularly MAD (Multi Attribute Dependent) Classes like Monk, Paladin or Ranger, that might be worth it. You could start at 16 instead, and either dump two ASI into your primary stat, or call 18 good enough so you don't miss out on the incredibly powerful, balance warping feats like Sharpshooter, Great Weapon Master, or Lucky. Or, you can take advantage of a filler feat. Also known as a half feat, a 'stat and something', or whatever else you want to call it, this gives you a +1 in a stat while also giving you a benefit. While not as powerful as other feats by design, they can be a great way to round out your character. So what are the options?
Strength
Athlete - Gives you a +50% jump distance and getting up from Prone takes less movement. The first part of that matters a lot more than the second, as jumping is quite good in BG3, and 50% is a large increase, especially for a class which cares about a Strength increase.
Heavily Armored - Gives Heavy Armor proficiency. If your class or Race combo doesn't provide it, this not only gives you the proficiency (which you could also pick up via a dip in another class) it also gives you the Str increase you may need. It allows you to totally dump Dex, which is a nice side benefit.
Heavy Armor Master - Reduces incoming damage from non-magical weapons by 3. This is actually pretty huge, I'm not sure if it's calculated before or after resistance from Blade Ward or Rage though, I'll have to test, maybe someone can let me know? Either way this can massively impact a character's survivability.
Lightly Armored - Gives proficiency with Light Armor. Not worth it for characters who care about Strength in any build I can conceive of.
Moderately Armored - Gives proficiency with Medium Armor and Shields. Same as Heavily Armored, you need to care more about the Strength increase than the benefits you would get from a dip in another class. Less worth it from my perspective for Str based characters than Dex, in part because most folks who care about Str likely already have this from another source.
Resilient (Strength) - Gives proficiency in Strength saves. Monk, Fighter, Barbarian and Ranger already have proficiency and aren't eligible for this.
Tavern Brawler - It makes no sense that this feat is in this list. It's absurdly powerful already, possibly the most powerful feat in the game, but here it is. Doubles your Strength bonus for attack rolls and damage when throwing something, making an unarmed attack, or using an improvised weapon. Would be worth taking even without the bonus to Strength, but you get it anyway.
Weapon Master - Gain proficiency with 4 specific weapons of your choice. There's no way this is the best option for you, in BG3.
Dexterity
Athlete - As above, but it's worse, since Strength determines jump distance.
Lightly Armored - As above, still not worth it.
Moderately Armored - As above. At first glance rarely worth it since Medium Armor only gives +2 Dex, but you get all pieces of medium armor (gloves, boots etc) not just the chest piece, which is the only piece which caps at +2 (with a notable exception). Plus you get shields.
Resilient: Dexterity - Gives proficiency in Dex saves. Bards, Monks, Rangers and Rogues are already proficient and aren't eligible for this.
Weapon Master - As above, and generally still not worth it.
Constitution - While not the primary stat for any class I'll list the options here for completeness.
Durable - Regain full HP during a short rest. A very marginal benefit.
Resilient: Constitution - Gives proficiency in Constitution saves. Note that Con saves are used for maintaining concentration. Not as good as Warcaster for passing those checks mathematically though. Barbarians, Fighters, and Sorcerers are already proficient and aren't eligible.
Tavern Brawler - As Above. Massively powerful, but it doubles your Strength bonus, so why would you not be increasing that bonus, rather than Constitution?
Intelligence
Resilient: Intelligence - Gives proficiency in Int saves. Wizards (the only class who would care about this) are already proficient in Int saves and are not eligible.
That's it! That's the whole list for Int, Wizards really get hurt by Observant not being in the game.
Wisdom
Resilient: Wisdom - Gives proficiency in Wis saves. C;erics, Druids, Paladins, Warlocks, and Wizards are already proficient in Wis saves and thus are not eligible.
That's it! As above, those with a primary stat of Wis are hurt by Observant not being present.
Charisma
Actor - Grants Proficiency and Expertise in Deception and Performance. Miles better than Skilled for someone who uses those skills, cares about Cha, and might otherwise take it.
Performer - Gives a musical instrument proficiency. Tough to see someone choosing this over Actor.
Resilient: Charisma - Gives proficiency in Cha saves. Bards, Clerics, Sorcerers, Paladins and Warlocks are already proficient in Cha saves and are not eligible.
That's all of them! I honestly expected more options for the other stats when I started, you've got multiple fantastic options for Str, one, maybe two good options for Dex and One good option for Cha, with nothing really for the rest. Ironically thanks to some items available in the game the Strength increase from the Strength options may not actually matter to you in the late game. Still, it's good to know the options. Setting aside Tavern Brawler, has anyone taken any of these? Which one(s), and how did it fare for you? Are there any feats which in your opinion Should have a stat increase kicker to increase their viability for a stat other than Strength, and if so, which ones?