Fashions have a way of returning after a generation or two. But there are some that should just be forgotten forever. I think #1 on my list is the bustle. I know they are sometimes used in formal-wear and wedding gowns, but it’s hard to believe that women once wore them on a daily basis. How many of today’s women would go out of their way to make their butts look bigger?
A runner-up would be those tall pointy hats that medieval “maidens in distress” wore.
Codpieces (men) and ruffs (both)
Loincloths
Spats
Hey, tall pointy hats are still all the rage.
anything from the eighties
Too late, unfortunately. My mom has a few bad pictures of me. One she displays prominently in her home; it involves scrunch socks(two pairs, different colors), shiny neon bike shorts, a tied at the waist off-shoulder New Kids on the Block T-shirt, and big ass bangs with a high side ponytail. She will never get me again. I’ve noticed that the only people who are into ‘80’s redux’ are the kids too young to remember it or even be born yet. /hijack
Togas and poodle skirts are two I can think of that will only ever be costumes, not clothes.
The Puffy Shirt, for that pirate look.
Nehru jackets.
Nothing screams “eighteenth century” like periwigs and knee breeches. They’re now frozen in time as a historical costume forever.
I’d wear one. (Point in fact, I have.)
Would also wear one.
The Pith Helmet has, alas, had its day and is no longer de rigueur for the discerning explorer, adventurer, or traveller to exotic locales. 
Weapons as jewelry. The small sword was the most evolved form.
Hoop skirts and farthingales - Much too cumbersome for the average woman to wear on a regular basis (the exception being wedding dresses, but they’re purposely designed to be anachronistic).
Togas - except for drunken frat boys, for whom a bedsheet toga will always be the garment of choice.
Puffy breeches - as popularized during the Elizabethan period, when poofier was better. Bonus points if they’re slashed to reveal a second, even poofier, layer beneath.
PS - 18th C style knee breeches did make a comeback a few years ago - albeit in the form of women’s capris (few men are willing to wear their pants that tight any more… such a pity). I have a couple of pairs in my wardrobe, actually. 
Everything from the '80s is back in fashion. It’s like my nightmares are throwing up. For men, bits of the '20s to '40s (I’m not expert enough to be more specific) also appear to be back, at least around here.
British judges aside, I don’t think powdered wigs are ever coming back.
I think your username was throwing me off. I could have sworn you were much older and male (with, in my mind, a big walrus mustache…sort of Wilford Brimley like).
Chastity Belts
Chain mail.
Puritan hats (for men) and bonnets and collars (for women).
Gargantuan Marie Antoinette wigs.
15th century pointy shoes.
Fig leaves.
Someone needs to do a Google search.
Yeah, my friend and I were talking to some 20-something year old guy in a bar a few weeks ago and he was telling us about how thishorror has come back.
Why are those jackets a “horror?” I had one ca.1983 or thereabouts.
It’s not something I would wear now, because it would look silly on a 47 year old man; but I don’t see why a young man would look particularly bad in one.
