Polearm Master is what a feat should be. It extends a playstyle and fantasy in a meaningful way that regularly highlights the strengths of the fantasy.

Mounted Combatant adds on to this more advantages outside of speed by granting you advantage on attacking smaller adversaries than your mount. Additionally, it takes a mount's largest weakness, a low HP pool, and offers you tools to mitigate that issue as the game progresses.

Moderately Armored basically is a shield proficiency for high Dex characters. That’s it. There are a handful of characters that’d consider taking it if they already have a decent Dex, or are working towards an off-brand high strength mid dexterity frontline warlock build or something.

At its absolute worst, Mobile is 10 feet extra speed. This stacks really nicely with other speed boosts and bonus action move options; any time you can double up on a bonus it’ll start to quickly become a notable element of a character.

Medium Armor Master commits the cardinal sin of RPG features by being boring. Don’t take a boring feat with meh number advantages. Actually empower your character with meaningful stat boots or new toys to play with.

Martial Adept is… troubling. Mechanically you’re getting a once a short rest button that lets you do a nifty combat trick for a feat. Compared to the majority of other combat feats, this is kind of a joke.

Magic Initiate is the best feat in the game for low tier play, bar none, and a perfectly serviceable feat for the mid-upper tiers. It is incredibly flexible, offers every character an extra spell slot, and gives you two new tools that can flesh out a character's utility and fantasy in a way few other feats can.

For a feat, if you’re one of these three classes, you can have a glorious +1 Dex and access to the light armors, basically giving you an AC of 12 + your Dex modifier. Without any armor at all, your AC is 10 + your Dex modifier. Put plainly, a feat is not worth taking your AC of 10 + Dex mod to 12 + Dex mod.

Keen Mind exists for the extremely pedantic of us out there. Do you need to know which direction is north to best determine your characters in game route? Do you need to know how many hours are left of daylight to the second? Do you need your character to have perfect memory skills?

You probably don’t need Inspiring Leader, especially if you’ve got other mechanics on your team giving out temp HP. It doesn’t stack, so it doesn’t play well with the other common avenues players get this bonus HP from.

Like most flat modifiers, Heavy Armor Master's damage reduction scales with the quantity of attacks it applies to. Twenty kobolds stabbing a paladin with spears will eventually bring it down… unless each of those 1d6+1 damage spears are dealing 0-4 damage instead of 2-7.

Heavily Armored; a feat offering a flip from an odd to an even Strength score or opening up a Strength based multiclass, and access to heavy armor proficiency. If you want access to it, you already need access to medium armor, gating it to either require another feat, or you need to be a barbarian, cleric, druid, or ranger who doesn’t already have a decent AC and wants a better AC.

Healing is just so abundant based on the current resting rules that I struggle to find a lot of value in healing that does much of anything outside of getting an ally off of zero. This does that, but that can be done in easier ways at a lower cost.

Elemental Adept promises players it’ll help them play their avatar of lightning or conduit of the ice god, but in reality offers up such a tiny boon that you’re better off just taking an ability score improvement to your spellcasting score. Elemental Adept is a trap that eats a valuable resource for players, and gives them next to nothing in return.

Durable feels like it belongs in a completely different game, like it fits for a one to two player campaign built around no magical healing, sparse long rests, and consistent waves of middling damage enemies. As it stands, even at tables playing with frequent short rests, you will almost always have better options to improve your long term hit point pool.

Defensive Duelist will absolutely help keep you alive. It's not something you build towards, but something you take if it fits what you’re already doing. A lot of the time just taking an ASI with +2 Dex is going to be as good or better, especially early on

Crossbow Expert is a neat feat to start with on a variant human, but not something that is so powerful I’d consider taking it over an ability score improvement. It makes otherwise near-unusable weapons usable in extra attack builds, but you could instead just use a longbow and not have any of the loading issues.

The play pattern Charger opens up is simple; you run at somebody, smash into them, and get rewarded for it. +5 bonus damage is a massive boon if you’re only making single attack rolls each turn. Five is roughly a bonus d10 damage to any weapon you can charge with, plus you get the benefits of having a way better range of engagement.

Athlete’s saving grace to me is its ability score improvement; if you have an odd number Strength or Dexterity, or maybe just really need to take that 12 to a 13 to open up a multi-class build, Athlete can feel “free”.

Alert is a feat for a very specific character at very specific tables. High lethality encounters where you’re playing an assassin rogue or other opportunist character jumps to mind as one such character. In most cases, Alert is just a series of minor passive bonuses you won’t engage with often enough where you’ll feel it was worth it.