I love that you can filter the TBR list by books that aren't part of a series, but I'd also love the option to specifically look for books in my TBR that are part of a series, and ideally have different filter options for books that are the first book in a series (for when I'm looking to start a new series) and books that are not the first book in the series (when I want to see what books I'm up to in the series I've already started).