Any high-gain Darlington transistor can be used on this touch circuit. The load can be formed by LEDs and the power supply isolated from the power grid.
This circuit is from an 80's electronic component manual. It has the way to simulate an inductor...
This is the receiver for the previous circuit found in the November 1991 Radio Electronics...
This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch...