Why be a bard? Bard's main shtick is support. Mostly offensive support by disabling enemies and letting your allies run rampant over them, but also by adding floating bonuses via your inspiration. You have all the key healing spells as well and can pick up any spell needed to fill in gaps in the party, making them rather versatile.
Goldenrod: Something you pretty much always take.
Deepskyblue: Grade A, and usually the most optimal choice.
Blue: Grade B, solid, if not quite optimal.
Black: Grade C, it passes, but don't expect much wow from it.
Darkviolet: Situation, most of the time you should pass on this, but there are corner cases that can really make this good.
Red: Grade F, avoid. At best you just wasted your choice, but it might actually hurt you.
Str: Probably a dump stat. Though valor bards can make this work particularly with expertise athletics. Grapple someone in a cloud of daggers, Hypnotize everyone then drag them around to compromising positions, Or make someone fall asleep, and get a free crit with a greatsword.
Con: Good for anyone, possibly more for your concentration checks than health. Though lore bards tend to stay in back.
Dex: Likely your secondary stat. Getting your disabling spell off first is great. Valor is likely to use this for an attack stat, and Lore needs it for AC as well.
Int: You're most likely dump stat. Though it's nice to know stuff.
Wis: Perception is important, and Wis saves can be very nasty (as you can prove yourself). Not a dump stat, but not a priority either.
Cha: You main stat. You could potentially play a low Cha valor bard, but you're probably better off as an eldritch knight or cleric for that concept. This also increases your inspiration dice, so it's hard to pass up.
Spellcasting: Bards are casters. Most of their power comes from here with a large selection of save-or-suck spells, as well as some healing spells. They get a moderate amount of spells (about 2-3 per level), but can only swap when they level. Spells are rated below.
Bardic Inspiration: Who want's a bonus! While you need to pre-use this, its versatility, being able to use it after a roll, and 10-minute window, there's a pretty low chance of it being wasted. Note it works on initiative.
Jack-Of-All-Trades: You are moderately good at everything. Note this works on initiative, dispel magic, counterspell, and several other things as well.
Song of Rest: A nice bonus at low levels, but doesn't scale well. Still, free HP.
Expertise: You're really good at something. Stealth, perception, and athletics are top choices. But what you want really depends on your build and campaign.
Font of Inspiration: This is like getting bardic inspiration all over again. Make sure to use them.
Countercharm: Pretty niche, you could easily forget you have this. Though it can come in handy on occasion.
Magic Secrets: This really opens up the class to do pretty much anything. Note that these count against your known spells, so it's not quite as great as it might first seem. There's a section below for choice spells to take.
Superior Inspiration: Possibly the worst capstone in the game. More bardic inspiration is good, but the condition attached means you'll rarely see it happen. So multi-class caster, you can keep your slots.
Valor: The big feature here is armor and shield, which is +4 or +5 AC. Making it good for groups where you don't have anyone to hide behind. You can mostly ignore the weapon. If your dipping hexblade 1, then take booming blade and any other subclass, like glamour. Hexblade gives you better melee features than as valor (though at the cost of a spell level).
What to do with weapons.
- Ignore weapons (14 dex, 20 Cha) and just enjoy the AC boost as a caster.
- Focus on them (20 Str/Dex, weapon feats, 16 Cha) and take non-save spells, like sleep, heroism, cloud of daggers, polymorph, animate objects, and force cage. Possibly getting smites or swift quiver at 10.
- Pick up Shillelagh and booming blade at 10 allowing you to use Cha to attack. For a solid gish option.
- Grappler with Expertise in Athletics + Shield Master + multi-attack + enlarge with your magic secrets let's you hold nearly anyone. Avoid save spells, but zones like cloud of daggers gives you a nice place to drag your enemies into.
Proficiencies: As mentioned, +4 or +5 AC is big.
Combat Inspiration adds a few more ways to use inspiration, particularly boosting AC.
Damage is generally the worse option, though still, it's nice to have, particularly on a crit or if you just need a little more to finish someone off.
Multi-attack: Not too impressive unless you've invested in weapon boosting stuff. You can ignore this feature and boost just stick with cantrips. Though it is nice for grapple + prone for extra control.
Battlemagic: Extra damage is good. Even if you only have 14 Dex as a caster it's worthwhile to hold a hand crossbow. Note you can attack before or after you cast, but cannot grapple+cloud of daggers.
Lore: The big feature here is Cutting words, which makes it much easier to use inspiration dice.
Magic Secrets helps round you out as a spellcaster, but it doesn't give more slots or more dice (you do get 2 extra known spells), so it's not that big of a boost. In a game where combat is minimal, lore bards are arguably the best class in the game. They fit into parties who have a good front line that can protect and defense (fighters, barbarians), and could use support and skills. Or you can simply multiclass cleric for AC.
Lore Bards multiclass better than Valor Bards because there is less overlap (i.e. armor). Life Cleric 1 is particularly tempting, with its armor, spell slots, bless, and guidance, and the grabbing aura of vitality as your magic secrets. Lore bard are best when you have a good front line and damage (barbarian, fighter, paladin), and need more support and utility.
Proficiency: You already have the ones you want, and jack of all trades give you half of this anyways.
Cutting Words: The fact that you don't need to pre-use it makes it a good bit harder to waste, though you still want to hand them out to your allies for any saving throw situations.
The to-hit penalty is certainly useful.
Ability checks are pretty tame, since you rarely see an enemy roll. However, it works on initiative, and cutting the solo dragons initiative is the same as boosting your entire parties. It can also let you burn 2 dice on the same roll, such as boosting an assassins initiative while cutting the dragons, or double up on a grapple check, though that's pricey.
Reducing damage isn't normally worth the die, but if you do it to an AoE, like fireball, that can add up. It also helps with concentration checks.
Additional Magic Secrets: 2 extra known spells. Damage spells don't scale as well, and bard already has good control and support spells, so it's not as impressive as it may first appear. Still, it's good to fill in any gaps in the party you need. Also, consider a better attack cantrip (eldritch blast).
Peerless Skill: You can now boost your own initiative, counterspell / dispel, and skills, but your dice are really getting stretched. This does combo with expertise, to allow you to get extraordinary skill checks. And if you take something like glibness and you can bluff a god (15 glibness + 5 cha + 6 proficiency + 6 expertise + 6.5 peerless skill + 6.5 cutting words insight penalty = 45). But you'll probably never face a DC that's higher than 30.
Glamour: Great for RP campaigns, as this let's you control crowds. Best in campaigns with more time for dialog, and ranged allies, as the free movement can get people out of trouble. Like lore bards, dipping for armor can be a nice bonus. Less so in a dungeon full of monsters with a dedicated tank.
Mantle of Inspiration: Better than cutting words if the damage is spread out, and for ranged parties that like to move. Note
Enthralling Performance: Great RP uses, but you already need a captive audience. Come level 6, you can command them around for a minute.
©Mantle of Majesty: A good feature, but competes with other concentration effects (hypnotic pattern). The auto-fail doesn't help too much as most charms take concentration, but works with Entraling Performance.
Unbreakable Majesty: Powerful defense with a Cha save, and even if you get attacked (not even hit), you get a boost to retaliate. On top of that, it's short rest recharge.
Blade: Blade flourishes aren't much better than the default bardic inspiration, except that you use them on yourself. But it also means more spread out stats. Best if you're going solo, and need versatility to be in melee as well as spells. This doesn't mesh as well with hexblade, since you can't use blade flourishes with booming blade, but still better than valor.
Bonus Proficiency: Medium armor can save you a few stat points, but you're likely to go Dex anyways.
Fighting Style: TWF is probably the better option here, as if your using insperation dice on yourself, you don't have other bonus actions.
Blade Flourishes: Note that requires an attack action, and thus does not work withbooming blade.
*Defensive Flourish: Your best bet, giving you AC.
*Slashing Flourish: Only good if you're surrounded by kobolds.
*Mobile Flourish: There's rarely a reason to push, and 5' won't cover much.
Extra Attack: Keeps you slightly above cantrip damage.
Master Flourish: Another feature that just keeps you slightly above cantrip damage.
Whispers: Some nice RP features, but they are just variants of spells you could cast anyways. At least they don't require concentration.
Psycic Blade: There's little reason to make melee attack, but the damage high enough to be worth if you do hit, and especially on a crit. Better if you dip hexblade to get booming blade.
Words of Terror: Cause Fear as a ritual.
Mantle of Whispers: A variant of Disguise Self.
Shadow Lore: A long duration Charm Person.
Races: Anything with +Cha/Dex/Con is good, and any other defensive bonuses. Alternate Humans (Inspiring Leader), and Winged Tielflings are top options. Dragonborn work nice for the melee type. And mountain dwarfs are good if your party is squishy.