Don't wear dancing shoes when riding.

it could be almost anything from a slightly loose pedal, noise cleat (if riding cliples), to a loose BB, to .....

Like all pedal synchronous clicks and creaks, it's a long diagnostic process.

While I normally try to analyze and test the most likely possibilities, the list here is too long. So I take out "gee, how could have I missed something so simple" insurance and work from the easiest to confirm or reject to spare myself unnecessary wasted effort. Start by removing one or both pedals and substituting others known to be OK, or reinstalling the same after cleaning and greasing the threads and mating faces.

Also check for easy stuff like a FD cable bent so it touches the crank or can tap on the frame, a chipped tooth on the chainring, and loose chainring bolts. In short, eliminate ALL the easy to check things BEFORE moving to things like taking apart the BB.

As I said, it's a LONG list of possibilities, so some patience is needed.