A lot, and I've shared a few here years ago, but don't feel like looking for them.
An interesting bit: plenty of times, but not always, Giles is my father. In one, I was back in middle school (the one I liked) when Mom was with a bunch of terrorists attacking it, but luckily I had the best of both worlds (size and age with underestimation and adult skill and confidence). Later, I was talking to Dad who drove up, commiserating how crazy Mom could be when Giles drove up (in the car he actually drove in the early seasons, not as flashy as my dad's Mustang), and I said bye to him, because Giles had come to take me home. There was nothing weird about it, and Dad acted as if it was normal.
Though in one I went to find Buffy for help (can't remember why, but it had to do with a family reunion in Texas), couldn't find her, but Giles came along. It was funny because he was commenting on actual plants and vermin in Texas saying these are definite signs of an impending Apocalypse with me telling him, "Naw, it's always been like that." 😀
I've dreamed of Buffy plenty of times. We were shopping together once.
A lot of times it's an episode, which I may or may not take part in. I had a nightmare of Angelus after me specifically once.
A fun one, one of those where I wake up and then catch one quick dream before getting up, was of a Faith trailer that could actually happen (but the movie was clearly going to insult Buffy).
A creative one was where Dawn and her class went on a field trip, but some pollution monster that breathed out its fumes, a spirit of fury for nature, was a problem, and Buffy had to get Spike who wouldn't need to breathe it in, and even hoped some of the mercury would add some kick to the whiskey he'd already drank. (He was dusted toward the end by a shock ending, but he ended the pollution demon first.)
A really complicated one was Willow using magic to help soldier Xander back up and somehow get him into the new Initiative, but somehow the Initiative turned it around and Xander was the Big Bad, but in the same way Angelus (or even Dark Willow) was, trying to save him from himself. I can't remember the details of that one.
One unusually interesting one didn't feature Buffy, but somehow I found myself in a parallel world. Skipping other parts, I got arrested and was placed with others who also had "invalid ID" and was angering and freaking a detective out as we both talked about Buffy, which the cop had never heard of and thought we were messing with her head.
One bothersome one (I don't think ever shared here before, probably because I don't want to talk about his background, though this was many years ago), a boy I was helping to raise (and was watching Buffy) dreamed his dead father came to him as a vampire, but then I, who was also Buffy, dusted him. He then realized he was a vampire now as well and I/Buffy chased him until he woke up. Not that this got him to stop watching Buffy. (Hush was his favorite ep that he watched over and over despite all the Gentlemen nightmares he had.)
I've had no such dream in years.