I have to admit, Buffy the Vampire Slayer (the TV show, not the awful movie) was a guilty pleasure of mine back in the day. This video showcases some, but certainly not all, of the creepy demons from episodes of this series.
I liked when Ethan Rayne turned Giles into a Fyarl demon. That was an unexpectedly funny episode. The Halloween episodes were great too, especially the one where they unwittingly conjured a fear demon at a frat party. The final reveal of that demon was priceless.
BTW, I used to go by the name MmFashnik on a BTVS chat room back in the day. Remember that unpleasant fellow? LOL