The ISO has rejected two symmetric encryption algorithms: SIMON and SPECK. These algorithms were both designed by the NSA and made public in 2013. They are optimized for small and low-cost processors like IoT devices.
The risk of using NSA-designed ciphers, of course, is that they include NSA-designed backdoors. Personally, I doubt that they're backdoored. And I always like seeing NSA-designed cryptography (particularly its key schedules). It's like examining alien technology.