I’d argue that there are at least two apps on Android for every available niche; you just need to find them. This is true for most products, but the one that I’ve found most difficult to replace is Google Maps.
My favorite Google app by far, Maps is useful for commuters, explorers, tourists, and restaurateurs. It includes info beyond mere navigation and community input that adds further richness to the experience. It’s a hugely capable and unique app that provides an almost unrivaled experience. “Almost” is the key word here.