Warframe by Digital Extremes
The traditional view of free-to-play games is that they are more akin to pay-to-function games as they are littered with time gates that cripple the playability of the game for the sake of a few pennies. Warframe doesn't follow this model - it provides rich and engrossing environment set across Earth's solar system that doesn't shove micro-transactions down players' throats. Instead, it just happily plays along and if the players want to buy some extra gear or improvements then they can, if they want. It's very similar to Path of Exile in that it doesn't insult the player base by creating a lesser experience for those who don't pay vs those who do.
In this episode of The Sausage Factory, show host Chris ORegan talks to Sheldon Carter, COO of Digital Extremes about the creation of Warframe.