The console terminal
By default, GNS3 use Putty on Windows and the system terminal on other operating systems. But you can change it and configuration for multiple popular terminals are provided.
In general preferences console applications, you can edit the command use to start the console application.
And choose a predefined command
If you choose custom and save you can add a non-supported terminal to the list.
In the command, you have special string like %h that will be replace at execution.
If you right click on a node you can open a different terminal.