Streamer[1,2], formerly pro gamer[3]. “Creator” here is a clipping of “content creator”, an overtly ad-industry term that makes me a little sad(der) each time I hear it but is unfortunately universal nowadays, especially for people making videos (as we don’t really have another umbrella word for that).
[1] https://www.youtube.com/channel/UCsHlla-bq0C_2OtEy8s2_Sg
[2] https://www.twitch.tv/kinggeorge
[3] https://liquipedia.net/rainbowsix/KingGeorge