I am a solo player and lot of people I speak with are looking for tool that can cover a lot of these core areas. As we are stuck using several tools such as obsidian, foundry etc, instead of one central tool.
A lot here I love, as stated above the agnostic support, ability to load card decks, hex maps (generation and custom maps with assets imported), basic orcale system, and pdf support (mark ups tools and form fillable).
Games like OSE, Across a thousand dead worlds, hostile, Astroprisma, machine gods of the noxian expanse, and things like West end games 2d6 star wars are some examples.