The new List field is great for grouping repeating content, but it only supports basic field types right now (text, image, date, link, and so on). It would be really useful to also add Reference and Multi-reference fields inside a List, so each row can link to items in another collection, for example connecting each row to a related book, category, or tag. Today those relationships only work as top-level collection fields, which means I can't build them per row inside a List. Supporting nested references would make the List field much more powerful for structured, relational content.