Metaobject selection in block options

We are building an app that allows users to create sections of content for their online store. What we’d like to do is store this content in a metaobject and allow the user to select which content to output in our theme app extension block. The trouble is that I’m not seeing a setting to allow selecting metaobjects. Only products, articles, etc.

Is there no option to do this right now? Is there a user friendly alternative? The only thing I have thought of is to ask the user to copy in an ID for the metaobject they want to output but that’s not exactly a nice experience for them.

Thanks!