[EDIT]: A few additions/corrections in bold
Ah, very nice thread Nat. Not sure how I missed it

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Here's my contribution:
BarbonYou can get Barbon's number by being quick-to-the-punch. If you approach Barbon and preemptively dodge his round-house with a roll, he'll be vulnerable briefly to anything. If you manage to corner him you can lock him down. Simply dodge his get-up cycle, attack, rinse-repeat.
JackIf Jack is down and there are no knives, you can avoid his get-up punch and stun him with a diving attack. Works somewhat like the trick with Antonio, but there is no room for error when timing Jack's punch.
SoR2 JetAfter any of Jet's "blitzes" he will be totally vulnerable and sometimes he'll be planted (but still able to move), allowing you to do combos or even grab him. If he's not planted after a Superman, then he will be after his swoop kick. Which attack he is planted from is random
RavenAnother weakness... back attacks, especially Roo's. If you turn your back on a kick-boxer, you'll provoke his slow-as-snails, rising-knee, which makes him vulnerable after a short time. A moment after he hops, you'll be able to back attack and knock him to the ground, this is your chance.
Doesn't have to be a back attack, of course, since not all are safe to use.BearAdditional ugly Ass strategy: This is Bear's biggest weakness and if you stay above or below him at a fair distance he will always try to use it.
AbadedeAbadede's body dive makes him very vulnerable but he's very likely to move away if he misses. If you manage to catch him, however, you can have a few free pokes (don't get greedy) and grab, just make it fast. You can provoke body dives by crossing from above and below at a fair distance. This will sometimes make him want to do his poke combo. It's a fairly safe strategy if you stay frosty.
SoR3 JetLike SoR2 Jet, he plants himself but only after his
superman attack. You have to be extra careful when provoking him to do it and very fast to dodge.