Harry lythall has done some good projects, is that the fm transmitter.
I have a old telequipment 'scope I use now & again, I seem to recall it has gimmicks in it, I spose you could even use them as a trimmer.
In about 1960 (?) I made a crystal radio. The coil/inductor was made of wire on a toilet paper tube. Like in the picture I had a version that used a razer blade as the diode. Then I got a real crystal. View attachment 124121