Discord History Tracker - Discord History Tracker is a great tool that enables you to select chat history and save it in your private conversations, servers, groups, and then view it anytime without needing an internet connection.
Omegle - Omegle is one of the most popular online chat website allowing user to communicate with anyone without registration.
PieMessage - iMessage on Android
Chatrandom - Chatrandom provides medium to users for having chat at random with different users around the globe.
Discord Chat Exporter - Discord Chat Exporter is a useful and open source solution that makes it easy for you to export Discord message history from any channel and then view it offline.
LuckyCrush - Live random video chat