Most significant mods in Skyrim's modding history

Hi all,

I'm really curious what you all would consider to be some of the most significant mods in skyrims modding history. Mods like Falskaar for being a pioneer in creating large, dlc sized mods, even if it might be a bit dated by today's standards.

I think the history and community of skyrims mod making community is fascinating, and I'd like to know more about and discuss what are considered by people to be some of the most groundbreaking mods, either as proof of concepts, or their technical innovations.