The Green Giants became so famous in Waterdeep that in time they were simply "the Giants"
Continuing on with Names for Adventuring Parties you will find a couple of tables on plurals.
Heroes, Avengers and Angels
There are more adventuring names beyond the "Fellowship of the Ring" template presented in my first Adventuring Party Names.
The Avengers are a well known group of heroes and the Companions would eventually become the Heroes of the Lance. Adventurers will often become a group associated with heroes, companions. The Avengers and the Companions were just known as such.
Use the plurals below either with an adjective "the Lucky Blades" or on their own "the Blades". The Group Type table can be used as another option along with the Adjectives in the first Party Names tables
Adventure Names - Plurals