One styling fad was that of the "fencer's mask" grille that started in the 1935 model year, peaked in 1936 and was largely done by 1937. These grilles were convex affairs that extended engine compartment ensembles about as far forward as the fronts of the fenders.
Which I think is why the fad collapsed so quickly. Even in fairly minor frontal collisions, fenders and grilles could suffer damage. The fenders could be pounded back into shape fairly easily in such events. But the grilles with all their decorative bars and other details were more expensive to fix or replace. So 1937 models featured grilles that were moved back a short ways and lost much or all of their convex shapes.
Roughly two-thirds of American brands took part in the fencer's mask fad. Those that essentially didn't included Cadillac, LaSalle, DeSoto, Ford, Lincoln-Zephyr, Packard and Studebaker. Those that did are shown below.
1935 Oldsmobile
One the first fencer's mask grilles was on redesigned 1935 Oldsmobiles such as this one I photographed in Brussels a few years ago.
1935 Pontiac with actress Helen Twelvetrees
The other early "mask" was on the '35 Pontiac that shared the Olds' body. It also was the first year for the brand's famous (at the time) Silver Streaks.
1936 Buick - Barrett-Jackson photo
When Buicks were re-bodied for 1936, they too received a fencer's mask style grille.
1936 Chevrolet
The Chevrolet version's convexity was more restrained.
1936 Chrysler Airstream - for sale photo
Chrysler's fencer's mask fronts were extreme versions of the style.
1936 Dodge with movies star Ginger Rogers
Dodge shared Chrysler's body, but its grille is more restrained.
1936 Plymouth Mayflower - Mecum Auctions photo
Chrysler Corporation's entry-level Plymouth's grille thrusts about as far forward, but the painted central strip visually counteracts part of the convex effect.
1936 Hudson
Hudsons were redesigned for 1936 and received an especially fussy convex front.
1936 Nash Ambassador
The Nash fencer's mask version was clean-looking and raked back.
1936 Graham Cavalier - unsourced photo via Flicker
Like Plymouth, sheet metal diminishes the fencer's mask appearance on the Graham.
1936 Hupmobile - Streetside Classic photo
Hupp's grille is raked back in Nash's manner but nevertheless follows the fashion.
2015 Chrysler 200
This recent Chrysler 200 does not have a fencer's mask grille. But its above-the-bumper grille-plus-headlights ensemble illustrates a theme on current cars that strikes me as being just as fad- or fashion-like as those grilles of 80 years ago were.