If you need to develop a custom tab, it is possible to design your own and you can also share it.
To develop the custom tabs, continue reading at https://msdn.microsoft.com/en-us/microsoft-teams/design where you can learn more about how to build your own tab and the best way to accomplish your goal. You can see samples at https://msdn.microsoft.com/en-us/microsoft-teams/samples.
The following screenshot shows the sample Bing Map tab integrated into the channel: