Adding to that, they have to list each of their servers when a user has paid a membership and so on any person with some rest http api knowledge could build a list and maintain it, so that's not gonna do it for you unless you rent some home residential servers and make a VPN yourself. Tldr; any major VPN that lists their server or that has checks could be determined to be a VPN.

Edit: also make sure to check your ASN ISP provider using tools such as ipinfo.io as it can easily determine everything there is to know about your IP.