@RukshanJS Greetings I am also a Synfig contributor just like you. Don’t think like an idea is taken or not. Just make a proposal explaining your approach to a particular project.
Do refer to this discussion to know more about GSoC and you will get most of your doubts cleared.
For Contribution in synfig, I would suggest you to refer to the official synfig-docs, and try solving some good first issues. Don’t forget to fork the repo [^_^]
I am also a Synfig contributor just like you. Don’t think like an idea is taken or not. Just make a proposal explaining your approach to a particular project.