Back in December, I submitted a feature request to include a post type selector for related posts since the query loop only chooses from the default post type. Related to this would be the ability to pull data into a post cards loop based on a custom value set on the post/page. Here is my scenario:

I am building a biography layout (which could be either page, post, or custom post type) and I need the ability to use three or four different post card features using distinctive post types – articles, events, speeches, or others. These need to pull data based on the person or other value – likely a custom field or fields common in each of the related post types.