The documentation for the GridToolBar here describes Add, but ExcelExport is also seen in the demos: https://docs.telerik.com/blazor-ui/components/grid/toolbar#built-in-commands
I imagine there are other built-in commands that are valid in the GridToolBar as well.
Thank you for noticing, Steven, the article should be updated by the time you are reading this with the two other currently available commands for excel and csv export.
You will find your Telerik points updated as a small "thank you" for bringing this omission up.
--Marin