GameVox is described as 'Voice, video, and text chat platform for gaming communities, built by LightSpeed Gaming — a small, independent company with well over a decade of experience in voice communication and game server hosting. Self-funded. No investors, no ads, no data sales' and is a Group Chat app in the social & communications category. There are more than 10 alternatives to GameVox for a variety of platforms, including Windows, Linux, Web-based, Mac and Android apps. The best GameVox alternative is Element. It's not free, so if you're looking for a free alternative, you could try Element or Discord. Other great apps like GameVox are Mumble, Stoat Chat, Zulip and TeamSpeak.
It's not a comparable alternative because Garena is comparable to Steam's chat.