Buckets, impression limiting and large banner limiting are the three features that we can move from cookies to LocalStorage right away.
As per T131319, for now, we'll leave out the decookieing of GeoIP and banner hiding after close button clicks and donations. (GeoIP is used a lot beyond CentralNotice; changes there should be part of a wider discussion about removing it from CentralNotice. For banners, hiding, we can't easily move to LocalStorage because our current way of hiding banners over multiple sites wouldn't work.)