Paradox takes games already made, sent by email to newgames@paradoxinteractive.com. It published Colossal Order’s Cities games and bought the studios Triumph and Harebrained Schemes.
“So if you have a game (not a game idea) you feel fits Paradox’s portfolio, feel free to get in touch with us.”
“newgames@paradoxinteractive.com”
What it says it looks for
“We are a company that has become known for smart games designed for smart gamers.”
What it has bought from outside
2011
Cities in Motion, later Cities: Skylines from Colossal Order
“One of Paradox Interactive's more notable publishing deals was its agreement with Colossal Order in 2011 to publish its Cities in Motion transportation simulation game and later its sequel Cities in Motion 2.…” en.wikipedia.org
2017
Triumph Studios (Age of Wonders, Overlord) from its founders
“Paradox Interactive acquired the Dutch game development studio Triumph Studios, the creator of the Age of Wonders and Overlord series, in June 2017.” en.wikipedia.org
2018
Harebrained Schemes (Shadowrun Returns, BattleTech) from its founders US$7,500,000
“Paradox Interactive acquired Harebrained Schemes, the maker of Shadowrun Returns and the Paradox-published game BattleTech, in June 2018 for a fixed price of US$7,500,000 and 25% of the earnings of Harebrained Schemes excluding publishing cost in the next 5 years, to the extent they exceed the…” en.wikipedia.org