Right now if you have a Thrumming Hivepool or 4 in the deck, playing things like Cavern of Souls or Leyline of Transformation won't include Slivers in their default suggestion list upon playing them - forcing you to type it out every time. In contrast it feels like having a single bird or avatar in a deck will populate those lists with that type. It'd be really great if Arena recognized that someone playing with Thrumming Hivepool probably cares about Slivers (which are repeatedly listed and interacted with in the card text) and would want that as a quick option.