UPDATE: And it's been patched. According to Anthem's community manager Jesse Anderson on Twitter, "We've reduced the chance of high rarity items in non-world event chests in free play. This applies to all difficulty levels".
ORIGINAL STORY: Anthem has only been available for Origin Access Premiere subscribers for four days, and already hardcore players have reached its endgame and found a way to completely break it.
Once you complete the story and reach level 30, you begin the grind of Anthem's endgame, which involves running Strongholds (similar to Destiny 2's Strikes) and completing Legendary Contracts (randomized missions) at progressively higher levels of difficulty. At level 30, players will start out at Grandmaster 1 and work their way up to the excruciatingly difficult Grandmaster 3, which ramps up enemy health and damage to a degree that a mission that normally takes 20 minutes can take an hour or longer. The reward for persevering through these jumps in difficulty is an increased chance to net Legendary and Masterwork gear, which gives your javelin exosuit a massive boost in power but are also incredibly hard to get.
But clever players have already found a way to skip that entire grind and get the best loot right off the bat. "There is a farming method found in Anthem, in which you're just running around the map on freeplay and you loot chests over and over again," says YouTuber Aztecross Gaming in a video about Anthem's endgame. "Pretty much one entire rotation of these chests could get you at least a Masterwork if not a Legendary."
How it works is that players are going into Anthem's Free Play mode, which allows you to explore its open world map at your leisure, and finding the chests that spawn in all sorts of out of the way areas. Each time they open a chest on Grandmaster 3, there's a significant chance they'll get a Masterwork or Legendary item—but without having to endure the brutal difficulty of Anthem's actual endgame activities.
On Twitch, several streamers are making use of the method to quickly farm the best gear in the game without having to actually tackle difficult missions. You can watch streamer xGladd and his team entering Free Play, running the same route from one chest to the other, and then exiting Free Play and starting over. In the few minutes that I've been watching, multiple members of his team have earned Masterwork items.
If you want to try the method for yourself, we have a guide on where all the chests are found in Anthem so you and your friends can run a similar route and farm up some nice gear. It might be worth doing now, because I wouldn't be surprised to see BioWare patch this out pretty soon.