How do you get the Placeholder Icon?
Riot has not published how the Placeholder Icon is obtained. The client shows it without a description.
Is the Placeholder Icon still available?
Riot does not list the Placeholder Icon as a legacy icon.

Placeholder Icon is a 2009 League of Legends summoner icon. Its icon ID is 501.
Riot has not published how the Placeholder Icon is obtained. The client shows it without a description.
Riot does not list the Placeholder Icon as a legacy icon.