ASP.NET Core Tag Helpers are the best new feature and replaces html helpers to make programming Razor view pages fun and easy. This 4 minute sample video is from the course "ASP.NET Core Tag Helpers" on Pluralsight.com.
The full three hour course gives you everything you need to know to both work with all the Tag Helpers built in to ASP.NET Core as well as author your own simple and advanced Tag Helpers.
Check out the full course here:
In addition, here is a link to the documentation on built-in tag helpers written written by Peter Kellner