The Academy Awards. Oh, sure, the Emmys and Tonys have pretty dresses too, but what else is the point of the Red Carpet segment? Certainly not those little interviews. The Red Carpet is made for this trope.
The first three Blackadder series had quite a few, particularly Elizabeth's dresses in the second series.
Inara Serra is a registered companion, which means she leads a glamorous life. She has a few gorgeous dresses.
In "Shindig", Kaylee played Princess for a Day in a pink and white dress that loaded with flounces and frills on the skirt and has tiny puff sleeves (that according to Mal made her look like "a sheep standing on its hind legs"). However, Kaylee's dress was bought in a shop. This resulted in ridicule from the local Alpha Bitches, until Kaylee demonstrated that she knows things about spaceship engines, which instantly endeared her to the male half of that ball.
There were of course several other dresses worn at the party in "Shindig" including the one it "takes the space of a wink to remove" that had a fancy sash, and a layered skirt with each layer bunched into frills.
Hannah Montana had a number of outfits on stage, that started to turn into these when the show caught on and the budget went up.
Murdoch Mysteries: The show is set in the late Victorian era and in the beginning of the twentieth century, and many ladies wear gorgeous dresses. Two show's coroners, Drs Julia Ogden and Emily Grace, are seen performing autopsies in beautiful outfits (no scrubs for doctors yet), and whenever the characters go to the theatre or have a dinner party, the trope is played Up to Eleven.
If there was a fancy event in Road to Avonlea, then fancy dresses would be worn.A publicity still◊ shows Felicity in a red dress with dark red gauze over the sleeves and bodice, and the gauze is heavily trimmed with white lace.
Say Yes to the Dress often involves pimped out dresses tried on, although they aren't always the ones chosen.
Even the Star Trek series will feature this trope.
Lwaxana Troi of Star Trek: The Next Generation has several, given her high noble status, that she quite often reminds people of. Her wedding dress was particularly elaborate. The reaction when she showed up for her wedding in traditional Betazoid wedding garb (that is, completely naked) was marvelous.
Game of Thrones: Westeros has a sharp feudal class distinction, so if you are a woman you are wearing either some dirty sweaty rags or a Pimped Out Dress. However it's the royal personages like Cersei Lannister, Daenerys Targaryen and Margaery Tyrell who wear the most pimped out dresses in the most variety of styles. And Sansa Stark.