if its just a shower and no tub spout then it most likely must be in your shower head and if its a hand held shower head (with a flexible hose attached) it most likely has a bad seal or some other way which allows air to get inside and drain the water out slowly. The same can be for a shower with a tub spout diverter and the shower head has a bad seal thus letting the water drain down the tub spout and it can be a real slow leak to cause the squeaking noise 20 minutes later, my guess of the squeaking noise would come from the air being pushed inside the shower head.
If the toilet and shower are in an upper floor then there is a PVC drain for both that will drain to either the sewer or septic. If there is a vertical piece to this, as there is in my basement, then you actually get some dribbling and running sounds from the water 'falling' down that vertical PVC. I get this same noise from the washing machine on the main floor draining down to the basement.
You are probably hearing the hot water hitting the cold pipe which causes expansion thus the pinging sound. Drain speed could probably be clogged vent stacks try cleaning them out.
A bad starter might make a noise. The starter could also go bad with no noise or warning. However if the starter is making noise then there is a problem that could cause failure at any time
A bad compressor belt can cause a whistling noise while running the air conditioner. A bad engine can also cause this noise.
Sounds like the main pipe is clogged. That's the big drain pipe that all three (toilet, shower, sink) are hooked too. When you plunge the tiolet it pushes back up the shower and sink instead of going down the clogged main pipe. The main pipe might need to be roto-rootered out. You could try some super heavy duty, pour in drain cleaner first. It might work.
You could have blown your tire or it could have gone flat.
The thing that could cause a knocking noise in your car is the same thing that could cause it in all cars A rod that or a flat lifter. it all really depends on where the knock is if its higher and to the back of the motor, it could be a motor mount
An air leak.
A bad noise suppression condenser. Usually attached to the alternator.
A buzzing sound could be created from debris in the drain pipe. Try removing the P trap and clearing out any junk you find.
Stuck hydraulic lifter.