This online archive of SVG versions of logos [via] is much better than the 300-pixel-wide JPGs that image search will cough up. The emphasis in on tech brands and startups.
Another good source for vector versions of commonly-seen logos (for example) is Wikipedia.
Has there been a U.S. brand with more logos than Union Pacific? I'd suggest someone vectorize the lot, but some of those Victorian-era ones look like a lot of work.
In total, there have been 27 changes made to the Union Pacific logo identity since the mountain elk logo was first used to identify the fledgling "Union Pacific Rail Road Company" in 1868. Despite their continuous evolution, Union Pacific's logos have remained under the protection of active trademark patent for more than 100 years.
