Warframe is all about getting more powerful, and few in-game mods can give you a boost quite like Riven Mods. Riven Mods are extremely rare unique mods for weapons that can offer certain perks, ranging from increased rate of fire to more damage or critical chance.
How to get Riven mods
The main way to get Riven Mods is from Outings. Sorties are a special set of missions with modifiers that you can complete once per day. A sortie is made up of three different individual missions, each with a modifier. You must have completed the War Within story missions to have access to the exits and only level 30 war bases can participate in these missions.
Occasionally, you may be able to participate in a Special Tactical Alert mission, usually as part of a special event. These will show up in the alert bar of the navigation screen and will always offer a special reward. Sometimes this reward will be a Mod Riven, although these are rare.
Similar to Tactical Alerts, Gift of the Lotus missions appear as special in-game events, such as the game's anniversary, and can often reward you with a Mod Riven upon completion. They usually last 24 hours, which allows most people to take part. These are great because they tend to be high level rewards but simple missions.
Archgun Rivens is the only Rivens who can participate in the game on a regular basis, as he is part of the Arbitration Honors from Arbitration Missions. In Arbitration Missions, you will earn Vitus Essence, which you can then bring to Hexis Arbitrators at any relay station and exchange it for rewards. These include an Archgun Riven Mod for 35 Vitus Essence.
Almost by definition, Riven mods are top-notch items designed to be rare. They can be traded between players and a vibrant Riven Marketplace, where people trade Rivens for Platinum, can be found in-game. Normally, I don't advise people to buy Rivens, as high-end products tend to be grossly overpriced and not worth the platinum that people are looking for. You're better off cultivating the Daily Outlet and grabbing the chances to get extra Rivens as they appear.
If you want to buy a Riven you had better buy a bad one, then use the in-game mechanic that allows you to revive Rivens to turn it into a better version using Kuva.
