"ChaCha" family of ciphers aim to increase the diffusion per round while achieving the same or slightly better performance.The Aumasson et al. paper also attacks ChaCha, achieving one round less: ChaCha6 with complexity 2^140 and ChaCha7 with complexity 2^231
https://en.wikipedia.org/wiki/ChaCha20
Also used in:
https://tools.ietf.org/id/draft-agl-tls-chacha20poly1305-04....