Denver Broncos
The Broncos first helmet was brown with a single white stripe and white #'s on the side. The pic above is from the 9/16/1960 game at Buffalo. The color image below (provided by Patrick Scoggin), is from the 11/6/1960 game in Denver against the Oilers. The black and white picture below is from the first official AFL game held on Friday night September 9, 1960 at Boston. Also, note the infamous vertical socks!
Early 1962 "Brown Bronco Logo" Version. Worn for just a few games before switching to the white decal.
9/15/62 at Buffalo. Brown bronco logo
9/21/62 at the Boston Patriots - it's tough to see, but Frank Tripucka (18)  is wearing the brown logo. It's a little easier to say on the Bronco in the foreground.
9/30/62 at the NY Titans - it's tough to see, but Frank Tripucka (with ball) is wearing the brown logo.
No logo version, believed to be from a 1962 pre-season game. Picture courtesy of Pat Scoggin.
10/5/62 at Oakland. This was either the first or second game played after switching from the brown logo. Gene Mingo is the ball carrier.
1962-1965 Version
This is a nice picture of Goose Gonsoulins's helmet. Picture courtesy of Helmethut.
1966
1967 "Logo-less" version. Thanks to Patrick Scoggin from Endzone Sports for sending me this rare color image.
October 1977 SI
Helmethut repro of Floyd Little's helmet
From a fall 1987 issue of SI
1994 Throwback paying tribute to the style worn from 1962-1965
John Elway
Current Broncos Helmet