The fantastic thing about Pathfinder is that all the rules are released to the public, so things like this are completely legal, and thus we get a lot more of them than D&D gets. We’ve got Pathbuilder for creating character sheets, as well as the Pathbuilder encounter builder for GMs (as well as numerous other character and encounter builders—I just like these because they integrate with each other), Archives of Nethys for a very user-friendly rules reference, and on and on and on.

In D&D you have to rely on expensive tools with special deals with WotC (by the gods I hate Beyond and their double-dipping “pay a fixed price for content and a subscription for app features” business model—though the creators behind Beyond have gone ahead and done the same thing for Pathfinder with Nexus, if you happen to like their UX) or ones willing to basically pirate content and hope that WotC’s lawyers can’t get it taken down, like 5e.tools.