I love World Creator, especially the vegetation distribution pipeline. You can create some very realistic fields with it. Im going to check out impostors too - ive seen it a few times and wondered what it's about.
Stupid Rental. My Zbrush that I haven't paid for an update in years and is perpetual Trumps that on all counts.
Have a look at the amazing analysis of the technique, which Mark Khalil used to create stylized waterfalls for League of Legends.
Mark Khalil is a senior environment artist at Riot Games. He’s worked on a number of projects, but currently, he’s occupied with League of Legends. His main task is making those battle areas pretty. Specifically for Real Time VFX he made a short breakdown of the Waterfall, used on the Summoner’s Rift map in LoL.
Here’s an example of some of the references Mark used in his work.
This is how the whole process was organized. It’s very simple and straightforward, but at the same time it helps to build some amazing things.