Chekhov's Gunman: Early in the series, the girls help out a troubled kid who was being attacked by some thugs. A few years down the line they meet up with him again, and it turns out that he's actually Tim Drake.
Played Straight in Long Walk Down a Short Dirt Road while rescuing the Riddler from Arkham Asylum, the Captain and Techie get caught in the woods by a security guard. They stage a steamy kiss, leading him to believe they'd just been looking for somewhere to be alone.
Averted in All Bad Girls Go to Arkham a wrestling match between the Captain and Techie results in a brief make out session that happens primarily off screen. They are subsequently caught by the Scarecrow, who doesn't care what they're up to and doesn't find it hot in the least.
Discussed in Vacation Time Poison Ivy gives Techie a mind control kiss, resulting in the following exchange:
Al: What, that's it? That was so anticlimactic!
Poison Ivy: You wanted something steamier? There are no fanboys jacking off to this, you know.
I Was Just Passing Through: Anytime Jonathan does something even remotely nice to or for one of his henchwomen, it's for his own reasons. He does not care about any of them, not even a little. Or so he keeps insisting to himself.
Lethal Chef: Al is well established to be one of these.
Love Redeems: Played with. Scarecrow's time with the girls did give him some grasp of love and appreciation for at least some human life, but he's still a villain who experiments on innocent people with fear toxin.
Mama Bear: Don't mess with plants or children in front of Ivy.
Teens Are Monsters: The Pćan of the Bells is one of the more serious CATverse stories, and it starts off with a flashback to Crane's incredibly shitty childhood. A group of teenagers enjoyed hunting him down daily, beating the crap out of him, verbally abusing him, and more, purely For the Evulz. He was terrified that he might just be killed sooner or later, and the kicker? They weren't doing this to somebody their own age or anywhere near their own size; Jonathan was still a little boy. Not surprising that he turned out the way he did.