With the release of Rebirth Island Reinforced the Beenox introduced several new features to Call of Duty: Warzone. Along with the changes to the map they also added new legendary weapons. Even though they are not weapon blueprints, these legendary weapons give a definite advantage in the early game.
The new legendary weapons introduced to Warzone are very diverse and range from snipers (Swiss 31, Kar 98k) to shotguns (R9-0) to SMGs (MP5, MAC-10) and ARs (Kilo).
A Reddit user made a map with Warzone legendary weapons