Look up the name of an author you like, to see what others have thought about books you’ve read.
Search a faraway country (Estonia? Madagascar? Nicaragua?) or a place you’ve always dreamed of visiting (The North Pole? The Maldives? The Taj Mahal?): who knows what you might dig up?
Think about natural extensions of popular topics you’re already following. If you love photography, try specifics topics like fisheye or film photography.
Try longreads for of 1,000 words+ or wprightnow for responses to current events.