We can all do any of the baras in training mode, but in a real match, I feel the upper limit, even for most Japanese players would be a front dash. You'll see the occasional 236 or AD baras, but those are few and far in between.
Here's my arbitrary best bara list and some of this might overlap with what Spooky posted earlier. Feel free to shoot any of it down though! This list does not include back dash or super jump unless they're better than normal for some reason.
S RankKouma: 214C, 214A, 22C
---214C: Unbelieveable range, grabs limbs, good damage. If Kouma's around, some dunking better be going down.
---214A: Less range, about as fast as 214C, can lead to higher damage if you're in the corner
---22C: Not sure why you'd want to do this since 214C is available, but it's better than what most other characters have
Shiki: 214C, backdash
---214C: Stupid invincibility, if the first hit clashes somehow and the second hit comes out, he's got hyper armor for almost all of the 2nd hit
---Backdash: While it's been nerfed, it's still one of the best backdashes
Satsuki: 214C, 214A, 22C
---214C: Speedy, good damage, a little invincibility
---214A: Since it's jump cancellable on block or hit, it's pretty safe, and fast
---22C: 214C is probably better, but this has less positional requirements to land a combo after
Kohaku&Hisui: 214B, 624C
---214B: Instantly comes out and if you trade, Kohaku will usually recover before the opponent. As an added bonus, if you mess up and the opponent hits both Kohaku and Hisui, you take greatly reduced damage since proration and scaling are taken into account for hits on both sisters even though only hits on Kohaku will count for damage
---624C: Arguably the best Arc Drive in the game(Hisui's)
A RankMiyako: 214A, 214B, 214C, 22A
---214A is fast, 214B is slower but has stupid super armor, and 214C has really stupid super armor + invincibility
---22A a quick low hitting stomp
Nanaya: 214B, backdash, 22C
---214B is somewhat fast, but will get stuffed by almost anything if they're still attacking
---Backdash is still the best in the game
---22C is the safest fake out, but the power comes from being able to mix up 214A-C, and 22A-C since they all look the same
Warakia: 624C, 421ABC
---624C is Warcueid summon, and it's really stupidly good even though it costs 150% meter
---421ABC is the teleport, very quick recovery, but don't get predictable with it
B RankCiel: 22C, 214C
---22C is quick and will usually score a counter hit
---214C is actually very fast from close range and good damage, just make sure it doesn't get blocked...
Arcueid: 214B, 214C, 22C
---214B is quick and is safe on block
---214C is kind of a waste of meter, but it's probably the best bara
---22C has good invincibility and clash, but has pretty low range so don't whiff it
Akiha: 214A
---214A is pretty quick and often leads to counter hits for a free air combo
Kohaku: 214ABC
---214A and 214B recover before landing so it's pretty safe to do
---214C is only vulnerable to throws while she's in magical kohaku mode
Aoko: 214C
---214C, big stupid orb, what else do you need?
Hisui: 214C, super jump
---214C can sometimes lead to the CH of death, which is huge payoff, but it's average at best
---Super jump, fastest in the game
Mech Hisui: 214A
---214A missiles come out quite fast, so it might be applicable at the end of strings
Nero: 214C, 421C
---214C can trade hits sometimes, but tricky to use
---421C ex deer, if you can squeeze this out, you'll regain momentum immediately
C RankRen: 421 moves
---Cat teleports are slightly faster now, but still marginally useful at best
Hisui&Kohaku: Super jump
---Fastest super jump
Aquiha: Nothing
Vsion: Nothing
I'll probably edit this later as I realize how wrong some of this is, just off the top of my head