Boon and Katie's scenes together are full of these. In the middle of all the Wacky Fratboy Hijinx that the Deltas get into, their relationship is surprisingly sincere, showing that even criminally irresponsible pranksters are capable of true love. For all her snarkiness, Katie is always willing to stick by Boon and see the best in him, even when Wormer see the Deltas as irredeemable scum. Boon even takes Katie back without question after she sleeps with Professor Jennings.
Otter and Boon rescuing Flounder from Neidermeyer's verbal abuse by knocking out Neidermeyer with a golfball. Sure, it doesn't get him out of stable duty, but the fact that they're willing to stick their neck out for him at all says a lot about the Deltas' sense of camaraderie. For all of the shit that they give Flounder, the Deltas still see an insult to one of them as an insult to all of them. Especially awesome, considering Flounder probably didn't even know that the boys were looking out for him.
Otter speaking up for Flounder when the Deltas are reviewing potential new members. His frat brothers are so repulsed by the guy that they start throwing beer cans when his picture comes up on the slide show, but Otter manages to sway them by reminding the Deltas that all of them were just as confused and hopeless as Flounder when they first came to college. He even admits that he was a Butt Monkey himself back when he was a Freshman—which, for a Handsome Lech obsessed with sex, is a pretty big thing to admit.
It's a small moment, but Bluto trying to cheer Flounder up when he wrecks his brother's car.