Mergiraf
Mergiraf can solve a wide range of Git merge conflicts. That’s because it’s aware of the trees in your files! Thanks to its understanding of your language, it can often reconcile the needs of both sides.
You can teach Mergiraf a new language in a completely declarative way. It’s a nonviolent animal, so it prefers that over imperatives.
Where I think this would be useful is for some issues we hit at $DAYJOB merging configuration files, JSON in particular.