Over the past seven seasons, several characters have stolen, stumbled upon, or been gifted Valyrian steel blades. Valyrian steel is also hard to forge since it's not like other metals, hence the ...

For instance, Cregan Stark bore the Valyrian steel blade Ice, the same one that Ned Stark would wield over 100 years later on Game of Thrones...before it's used to behead him at the first season.