Im using iThoughts. It's Windows/Mac only though. I recently switched to Linux and trying to get it to work in Wine. I do believe you can create nodes without

Im using iThoughts. It's Windows/Mac only though. I recently switched to Linux and trying to get it to work in Wine. I do believe you can create nodes without any Hierarchy and you can always join the nodes into a hierarchy later. It's got great export features and a ton of other stuff. For me it's the best mind mapping software I have ever seen and I have tried a lot of them.