WAGO Lever Nuts
If you need to connect wires, especially different types of wires (braided, solid, etc) these things are amazing and keep your project looking neat.
We use these around the house, camper, enclosed trailer and even some of the connections on our robotic targets. They aren't a good choice for connections exposed to outdoor environments, but indoor applications are made simple.
It's hard to go back to a wire nut or crimp connector after using them!