I’m Angi K, a huge fan of 2D animation and an amateur animator myself.
I used to use Toon Boom Animate 2 PLE Edition until my Windows-based computer ceased to function. Since I switched to using Ubuntu, I’ve been looking into an alternative (because Toon Boom doesn’t work with Ubuntu. At all. Not even through Wine.), and came across Synfig Studio in the Ubuntu Software Center.
I’m still going through the documentation and learning how to use the software, but I really like this program, I like it more than Toon Boom, honestly! 
(the fact that all of Synfig’s features are free of cost kind of influenced my opinion, heh.)
Why hello there and welcome to the commute! Now here is your synfig lightsaber, book of force animation and cookie!..and no this is not a bribe to keep you here 
Please, blow up that to the four winds! 
-G