That's a JetBrains thing - they added loads of fantastic refactoring options to Visual Studio for C# which have now largely been integrated into the IDE directly. I've had an all-products subscription for close to a decade now and it's money well spent.
ReShaper was what kept JetBrains alive 10+ years ago and Microsoft couldn't release a new version of Visual Studio until ReSharper was ready for it due to how many people used/depended on it.
