My mom was up late one night cleaning, she set a picture of my dad which died a few years ago on our home bar flat. Her 2 friends came over at some point that night and commented on the picture, they left and shortly after, while my mom was in the other room, the picture flew off the bar and hit the wall across the hallway. There was nothing there that was visible that could've even knocked it off the bar led alone throw it off the bar.
When I was a kid I use to play hide and go seek at my friend's house, we thought it would be scarier in the dark because we thought it was haunted. About 5 years later we found out it really was haunted, their mom asked old owners if they knew who lived there before they did and her name was susey. My friend has told me sometimes when he takes showers at night, the lights flicker only when he's in the shower. One time when my mom was over there, she was talking to my friends mom and a candle flew off the shelf and landed across the room, with no explanation why. About a month ago when I was over there, I was sitting in the next room and I looked over at my friend while he was letting the dogs out the back door and the light just went out and he wasn't near the switch. And seriously when they moved in, there was a built in swing on their front porch, they had it taken down and you can still somehow hear swinging like it's still there.