If we rule out Star Citizen, since it received its crowd funding efforts off-site, the currently Kickstarting sequel to the original Monster board game, Kingdom Death: Monster 1.5, could end up becoming the most crowd funded game ever on the site. Its creators already funded a very successful, very expensive and very difficult game on the site, but this one is something else.
The detail on the miniatures is stupendous, which is why the game costs as much as it does. $1,666 is what it will cost you for the base game, all expansions and additions and all future stretch goals - but they won't all be delivered until sometime in 2020, which is a crazy long time to wait for a board game, especially when you put all the money down up front.
Still, as with the aforementioned Star Citizen, sometimes you have to wait a long time for games to arrive.
This is only for the additional expansions too. The Core game at the heart of Kingdom Death: Monster, will be delivered by Summer 2017, and what a lot of stuff will come with it. Hundreds of cards, models, figures, pucks and tools and bits, all of which enhance the depth and breadth of the game.
It's a Dungeon Crawler with Dark Souls overtones and some base building thrown in. There's tonnes going on, but you'll need to have deep pockets to net all of it.