That video was shot with a pre-release version of Groove Agent SE 5. Most if not all of the additional content you see is content shipped with Cubase but is not Groove Agent SE content, such as Hip Hop Vault (loops supplied for use with Cubase) and MPE Sounds Padshop (which, unsurprisingly, is content for Padshop). The release version of Groove Agent SE 5 only displays Groove Agent content by default, though I am not sure if there is an option to get it to behave as in the video. Even if there is such an option, it will not be that useful: whilst you can use any sample you like with Groove Agent SE, the best results in most scenarios come from using individual drum samples or, better still, proper Groove Agent kits.
If you want more Groove Agent content you need to buy it. Your best option is likely to be the full version of Groove Agent 5, either as a standalone product or as part of Absolute 4. Many of the Groove Agent expansions sold by Steinberg are listed as compatible with Groove Agent SE 4, so I presume they will work with Groove Agent SE 5.