Hobbyist magazines have published many guitar effects and a metric ton of other stuff over the past decades. Popular projects were measuring devices and power supplies (often called "lab equipment"). In the dark times (before inexpensive multimeters) a simple DC-voltmeter was a really attractive and super useful project. And of course, a variable power supply was an absolute must project for every serious hobbyist. Radios were a particular topic for ham radio magazines, of course. And amplifiers... many many amplifiers everywhere.
History is a part of my hobby in electronics. I greatly admire hobbyists who build these projects back then, and I would also like to pay homage to original authors. Many decades before internet hobbyist magazines and books were the only source for projects. And your local ham radio club or electronics club was the only source of help if something went wrong. For a loner like myself, that would ave been a good thing. Social aspects and all that. We are very privileged to have such abundance of information today!
I highly recommend you to try and build some of these old circuits. I'll present you good, bad and ugly from the past decades. And some of my favorites too.