None of the mainline villains really come to mind. My reading of her makes me want to say Ultimecia, but as a character she doesn't get the spotlight of FF VIII enough to really inspire much sympathy. Zemus, Exdeath, Kefka, Sephiroth, Kuja, Vayne, all not villains I'd call tragic.

I guess much as neither of the two are actually effective villains, Yu Yevon and Seymour come the closest. Yevon and the fayth I doubt grasped the full implications of their plan when they enacted it, they just wanted to save the home they loved, but when the full price for that wish became clear I'm sure they wanted out. And Seymour is an utterly broken man basically wanting to force all of Spira into a mass group suicide, and his arc could've been actually effective if he wasn't resignated to being "that asshole that keeps getting in the way of the party" and actually challenged the party's worldviews in some way. smurfing hell.

Really, just from what I heard, Delita sounds like way more of a tragic 'villain' than any of these.

Almost forgot about Caius Ballad. I guess he's near the level of Seymour, i.e. not really much of an effective villain, but he does have an element of tragedy to him.