Teevox is described as 'Twitch Multistream Player, made in Static HTML, React, Firebase' and is a Live Streaming tools and service in the gaming software category. There are three alternatives to Teevox, not only websites but also apps for Self-Hosted solutions. The best alternative is SimulTwitch, which is free. Other great sites and apps similar to Teevox are MultiTwitch.tv and Twitchster.
MultiTwitch.tv lets you watch multiple Twitch.tv streams at the same time (as long as your computer can handle it). Simply put the streams you want in the url. For example: multitwitch.tv/siglemic/cosmowright.