The OAKLAND PICTORIAL ARCHIVE contains a whole lot of views of Oakland from old postcard images, circa 1900's to mid 1960's. Here are some examples of early 20th century Oakland postcards not included in the OAKLAND PICTORIAL ARCHIVE.

Oakland downtown City Hall Plaza San Pablo Ave and Broadway postcard, circa 1915. Downtown Oakland, Broadway, circa 1920s
Downtown Broadway and Telegraph Ave postcard, circa 1920s. Postcard of Southern Pacific Station 16th Street Oakland, circa 1915.