Plains of Eidolon
The Plains of Eidolon update was released in October 2017 to PC, and November 2017 to consoles. The Plains are accessible very early in the game; however, much of the content is best played at a higher level. For example, due to the size of the map (it’s essentially an open-world map), players can best travel about using an Archwing, or an advanced warframe such as Titania. Newer players are unlikely to have access to these (and the ability to use Archwing in the Plains requires a device that can only be purchased from Clan research). Further, many of the new additions (weapon crafting, Eidolon hunting) are skewed towards late game. Certainly, though, you should spend some time in the Plains once you reach mid game, because there’s a lot of fun to be had, and there are certain items that can only be obtained from the Plains – namely, Gara (the glass warframe), Revenant (the Eidolon warframe), and Zaws.
Zaws are modular melee weapons – component blueprints are awarded by doing Plains bounties – and players can mix and match components to build a weapon skewed towards their preference – like polearms, but want it to be slow and crit-based? Sounds crazy, but give it a shot! This adds quite a lot of additional content to the game, as well as a whole bunch of things to grind for, but all in the name of fun.
In addition, you can now waste time mining and fishing! This doesn’t really do much initially apart from providing resources, but admittedly, it’s more fun than it should be. Realistically, given the bounties, the Eidolon, Gara, Revenant, fishing, and mining, there is a hell of a lot of content available on the Plains. Once you can handle enemy level 20 and above, get out there and explore. I should note that mining and fishing is the only way to grind significant reputation on the Plains, and grinding Plains reputation is important for the late game, but for mid game, it doesn’t necessarily need to be a focus.
On top of this, there is the Quills. The Quills are essentially another faction that are initially only located on the Plains (but you will also find a representative in Fortuna). They will have you out trying to take down the hulking Eidolons that roam the Plains at night, and you will be rewarded with things that will augment your late-game play. If it seems like I’m hiding things, well… that’s because I am. There are certain secrets in Warframe that should remain secrets. Play the Quests.