Standard Dimensions are fairly limited... technically I believe that the URL and Referrer will be captured by default. You can overwrite these (values, particularly referrer on SPAs)... but keep in mind that URL while available in the Raw Data, and Data Warehouse Exports, is not available in Workspaces (for that, you need to set up a custom eVar, generally at Hit level expiry).
Technically, Page (pageName) is also set by default as the main identifier for a page.. but when you don't set this yourself, it just sends the URL as a generic value. So it's highly recommended that you set up your Page Names specifically.
Other items which are captured by default would be location items (IP. Geo Country, Geo Region, Geo City - unless of course you are hiding the last octet of the IP, or obfuscating IPs completely, then I don't know how well the location information will be set).
Time dimensions, such as Year, Month, Day, Hour, Minute are all captured based on the timestamps.
Referrer Type, Referrer Domain are extended calculated data based on the Referrer URLs.
General usage dimensions like Browser, OS, Visit Depth, Return Frequency, etc are also all captured by default.
However, if you are going to use Adobe Analytics, it seems a shame to proceed with only the most basic of tags, given the strength of the tool is the ability to customize and create rich inter-connected dimensions that you can correlate far more deeply and easier than GA allows...