Navigate To Extension Methods
This command allows you to navigate from a declaration or usage of a type to all extension methods defined for this type in the solution. It is available when you invoke Navigate To on declarations and usages of types. You can invoke this command from the Solution Explorer, from the Structure window and other tool windows.
If the command returns a single result, JetBrains Rider navigates directly there. In case of multiple results, they will be listed in a drop-down where you can do one of the following:
Click the desired item to open it in the editor.
Select the desired item by pressing Up and Down and then press Enter to open it in the editor.
Start typing to filter results. Note that you can use CamelHumps here.