In Gex, each remote has a design that relates to the world it belongs to. There are level remotes and world remotes. World remotes are used to go to another map. The level remotes activate TVs on a map.
In Gex: Enter the Gecko, there are three types of remotes: red, silver, and gold. Red Remotes are used to activate boss levels, open gates, and eventually activate Channel Z to fight Rez. Red Remotes are gained by completing missions. Silver Remotes are used to go to bonus levels. Each level has two Silver Remotes. One is hidden for you to find and the other is obtained by collecting enough collectables. Gold Remotes are used to go to secret levels. There are only two ways to get Gold Remotes. One way is by defeating a boss. The other way is by beating a bonus level.
In Gex 3: Deep Cover Gecko, there is only one type of Remote. They are used to open up new levels. Gex can collect them by completing missions and by collecting 100 Fly Coins in a level. There is also a remote available for completing the training room.