Searching for mods (looking for mods for Tribes of the East).

Hello. You don't need a mod for this – it's a standard feature of the map editor.
To make it clearer: here's a video guide on Remix's channel. Starting around the first minute, it shows what you're asking about.
Guide on Remix's channel

That's completely different. I mean the ability to customize game modes when selecting a map in the game. There were also more complexities, such as intelligent AI, meaning I could choose any existing map and play with friends in a cooperative mode against the computer.