In the latest Patch 11.2 build, many recolors of old world weapons can be found from Phase Diving!
Learn more about Phase Diving in our 11.2 guide:
Phase Diving Guide
How to Obtain Phase-Lost Weapons
Phase-Lost weapons can be obtained from phase orbs, which can be seen while Phase Diving in K’aresh. These are visible once you get the Secrets of the Depths upgrade on your Reshii Wraps talent tree. With this talent, you have a chance of encountering these orbs in the world.