I can't share everything I found with you, not all at once. So I came up with a theme to build a selection around. Quite naturally, the first thing that occurred to me was alien terraforming. As a matter of fact, what occurred to me was transdimensional alien terraforming. Here's a wisp of a story for you.
The Old Ones had been waiting for aeons, in the seas beyond our universe. And now, at last, the stars were right. They could return. They burst asunder the doors separating their world from ours, and then they came inside.
The Old Ones strode across the earth, taller than the highest mountains, stranger than the depths of the seas. And everywhere they strode, they claimed. None could hope to oppose them.
They filled the earth with their alien ooze, remaking lands, plants, animals....
They repurposed buildings to meet their needs, turning even the simplest structures into portals of dread.
And, of course, they repurposed humans, too. They loved nothing better.
And so, at last, the dimensions were united. Into one. Big. Happy. Family.