WBBF

950 AM in Rochester, New York became WBBF (W Buy B Forman) when they were bought by the B. Forman department store chain in 1953.  They were a successful Top-40 station from that time up through the late 1970s before flipping to Talk in the 1980s. 

WBBF-FM went on the air as a listener-supported Classical station in 1961.  The above magnet is circa the late 1990s when they were an Oldies station at 98.9 FM.

At one time, WBBF also lived at 93.3 FM licensed to Avon, New York.

Los 40 Principales

Los 40 Principales is a chain of Contemporary Hit Radio stations in multiple Central and South American countries as well as Spain.  "Los 40" began in Madrid in 1966 as a Top-40 chart show broadcast on Radio Madrid and later on Cadena SER stations.  In 1979, 40 Principales expanded from an 8 hour show to its own network of stations dedicated to the Top-40 chart.  They became an independent network in 1987.

Beacon Radio

Beacon Radio went on the air from Wolverhampton, West Midlands, England in April, 1976.  The Independent Local Radio station is now known as "Free Radio" and broadcasts at 103.1 and 97.2 FM.

WTRI

1520 AM WTRI went on the air in 1966 and is licensed to Brunswick, Maryland.  They probably broadcast a Country format when this sticker was current.  The station was once owned by oddball politician and conspiracy theorist Lyndon LaRouche.  Recent years has seen a variety of formats including Standards, Classic Country, Spanish and Asian-centered programming as well as going silent multiple times.

WMVB

1440 AM WMVB (W Millville Vineland Bridgeton) airs a Variety format in Millville, New Jersey.  They were probably an Easy Listening or Adult Contemporary station when this sticker first appeared.  They stopped simulcasting on FM in 1988.  97.3 FM is currently WENJ, an ESPN Radio-affiliated Sports station.

WJSR

WJSR was a student-run station broadcasting from the campus of Jefferson State Community College in Birmingham, Alabama.  Interestingly, they shared the same frequency as another college radio station in the same city--Samford University's WVSU.  Apparently this wasn't a time-share agreement.  Both stations operated at the same time utilizing directional antennas away from each other.  WJSR was on the air from 1979 until 2014.

WERL

950 AM WERL is a News/Talk station licensed to Eagle River, Wisconsin. 

WAKO

910 AM WAKO went on the air in Lawrenceville, Illinois in 1959.  They currently carry a Classic Country format which is simulcast on translator W257DW at 99.3 FM.

KTEP

88.5 FM KTEP is a non-commercial, public radio station broadcasting from the University of Texas at El Paso.  Former ABC News anchor Sam Donaldson was the station manager there in the 1950s when they had the call letters KVOF.

KOTC

The coupons on the back of this KOTC bumper sticker dates it to 1995.  Given the slogan on the decal, they may well have been a Country station although 1996's Broadcast Yearbook says they carried an Adult Contemporary/Classic Gold format.  KOTC was licensed to Kennett, Missouri and went silent in 2008.  830 AM first began broadcasting as KBOA in 1947.

KGLA

1540 AM KGLA is a Spanish Tropical station licensed to Gretna, Louisiana just east of New Orleans.  They are also heard on translator K289AM at 105.7 FM.

KASL

1240 AM KASL is a Country station licensed to Newcastle, Wyoming.  They went on the air in 1953.

Radio Works

I'm not exactly sure what Radio Works was when they existed in the early 1990s.  I do know they were part of Communication Graphics, Inc. (still around, although now known as Comgraphx) a designer and printer of promotional marketing products including, I assume, radio station bumper stickers.  You can read their "manifesto" below which is printed on the back of the decal.
(Click it bigger)

WRNO

99.5 FM WRNO was a Rock station in New Orleans, Louisiana from 1967 until 2006.  In 1982, WRNO "The Rock of the World" became the first commercial shortwave station to broadcast from the United States.  They originally carried a separate Rock format but eventually began simulcasting WRNO FM's programming.  It's unclear if the top sticker was for the FM station or the shortwave station--or both.
The 100,000-watt FM outlet now carries a News/Talk format while WRNO Worldwide carries a Religious format.

WQRI

88.3 WQRI is an 800-watt station operating from Roger Williams University in Bristol, Rhode Island.

Mystery Sticker - F101

Nobody knows what station this "F101" bumper is from.  Do you?

CKKL

93.9 FM CKKL in Ottawa, Ontario went on the air in 1992 with a Hot Adult Contemporary format known as "Kool FM".

By 2003, they were a CHR outlet but dropped Top-40 for Adult Hits as "Bob FM".

CKKL flipped to a Country music format in November, 2014.

KSCJ

1360 AM KSCJ airs a News/Talk format in Sioux City, Iowa.  They recently celebrated their 90th year on the air having begun broadcasting on April 4, 1927.  The call letters stand for (K) Sioux City Journal, the newspaper which once owned the station.

WNEW

New York City's WNEW spent over 30 years as a Rock station--from October, 1967 until September, 1999.  Over the decades their format shifted from Progressive Rock to AOR and eventually included Classic Rock, Alternative, Active Rock and Adult Album Alternative.

A short-lived era of Hot Talk then took over which lasted until January, 2003.  At one point, their  ratings dipped to 0.7, an unprecedented level for a major market FM station and lower than many non-commercial stations in the city.

After time spent as "Blink 102.7" and "Mix 102.7", WNEW became Adult Contemporary "Fresh 102.7" in January, 2007 and eventually took the call letters WWFS.  The WNEW calls returned in March, 2016.

OFM

OFM broadcasts in English and Afrikaans on multiple frequencies throughout central South Africa.