The following links are to Websites useful for Communications-Advertising students and faculty:
Advertising Archives
Mid 19th Century to the present. Image types include: British, French, Spanish, & American magazine covers and illustrations; British TV Advertising Stills; Mail Order Catalogues; and Posters, Postcards, Menus, Theatre Programs.
Duke University Library Digital Collections
Several collections curated by the John W. Hartman Center for Sales, Advertising & Marketing History.
Vintage Ad Browser
Site draws from a variety of sources, including comic books, CD-Roms, websites, book, magazine & comic book scans, and more. Sister site called Cover Browser. Site claims Fair Use of copyrighted material.
Digital Public Library of America
In addition to advertising collections, another approach to advertising history is through digital images of daily life. Images of daily life can be found using this resource.
Ad Forum
Search 200,000+ ad capaigns and case studies from around the world.
[list is being updated]
In 2020, the Pollak Library ended its subscription to the Kantar/SRDS database due to unsustainable costs. 
The database was a media directory, providing lists of TV stations, newspaper bureaus, radio stations, magazine publishers, outdoor media companies, and more. Below is a "workaround" to not having the database: links to alternate/online lists of these media outlets.
NEWSPAPERS
US newspapers, by state: http://www.onlinenewspapers.com/usstate/usatable.shtml
California newspapers: https://en.wikipedia.org/wiki/List_of_newspapers_in_California
Ethnic newspapers: https://en.wikipedia.org/wiki/Category:Non-English-language_newspapers_published_in_the_United_States
TV STATIONS
LA/OC TV stations: https://en.wikipedia.org/wiki/List_of_Los_Angeles_television_stations
Top 100 TV markets: https://www.stationindex.com/tv/tv-markets
Top Hispanic TV markets: https://www.stationindex.com/tv/hispanic-tv-markets
RADIO STATIONS
US radio stations: state/city/genre http://radiostationworld.com/locations/united_states_of_america/radio_broadcasting/
California radio stations: https://en.wikipedia.org/wiki/List_of_radio_stations_in_California
MAGAZINES
US major magazines, by subject: https://en.wikipedia.org/wiki/List_of_United_States_magazines
US major magazines ranked by subscriptions/sales: http://www.mediacontactspro.com/the-top-500-us-magazines/
US magazines, popular in each state: https://www.w3newspapers.com/usa/magazines/
Library database, Ulrichs, of worldwide magazines & journals: https://libraryguides.fullerton.edu/ulrichs
OUTDOOR MEDIA
Top 376 Outdoor Media companies, ranked by # of signs: https://www.billboardinsider.com/us-out-of-home-companies-ranked-by-bulletin-faces/
Outdoor media media finder & directory (OAAA association): https://oaaa.org/AboutOOH/OOHBasics/OOHMediaLocator.aspx
ALL MEDIA
Gale Directory (Pull-down medu: Directory of Publications and Broadcast Media) This database likewise lists newspapers, radios stations, TV stations, etc., nationwide.
California Ethnic Media Directory This directory lists California ethnic media (newspapers/radio/TV) and is free to download from the Ethnic Media Services organization.