A clean and portable example of electronics would be Elecfreaks ‘Micro:bit Experiment Box”. This box has a screwed in frame with a bundle of banana clip wires to provide easy to make connections. In the kit, there are resistors from 100 Ohms to 10k Ohms, LEDs, Buttons, a fan, smart LEDs, a MOSFET, trimpot, a buzzer, a photocell an NTC. With a wide range of electronics pieces, you can teach students from all sorts of skill levels.
Below is a simple program that blinks an LED. all it takes is 2 wires and a bit of code!