If you're willing to compile it, Aseprite is a great option as well.
check my website for the latest tips - always updating with new content!
Paul Ambrosiussen released a new tool, which helps to optimize destruction simulation for usage in games built with Unreal Engine or Unity.
Procedural destruction simulation for a long time has been one of the biggest features of Houdini package. While a lot of developers still believe this technology only applicable for large-scalemovie production, you can actually use it in games as well. During GDC SideFX actually shared a bunch of awesome talks about the way this technology could be applied in games.
Most recently Paul Ambrosiussen released a tool, which may make the whole process of importing destruction simulation in game engine much more convenient.
It works great if you are building content for Unreal Engine 4, Unity, Maya or 3DsMax. You can get more info on the official website.