Depending on the fridge, you have a few more moving parts than what you listed. You mentioned the compressor, condenser and evaporator.
The compressor is essentially an engine. It has a motor and some type of piston system to compress the gas. For all intents and purposes, this is one unit. If it any part of it breaks, the entire thing will be replaced.
The evaporator is the coil inside the refrigerator is the part the blows cold air (technically it absorbs heat) inside the fridge. The fan motor is what you are referring to. That motor can go bad and more commonly ice can build up and hit the blades, but that tends to make a characteristic rapid ting ting ting noise. If you don’t know it, you’d at least recognize it as an “OMG what’s wrong” noise.
The condenser is the opposite of the evaporator. The evaporator turns liquid into gas, the compressor, compresses the gas which turns it into high pressure hot gas and the condensor turns it back into liquid which takes all the heat it absorbed in the fridge (plus any it picked up in the compressor) and dumps it outside the fridge. Again, the fan motor is what you’re referring to. That fan can go bad, it can get bent and hit things or dust (or anything else) can get in it’s way and hit it.
However, there’s a few other noises.
The refrigerant itself can make noise as it circulates. It tends to have either a hissing or a ‘water dribbling’ sound, but it’s a noise none the less.
Depending on the style of your fridge, you may have 2 or 3 circulating fans. Their job is just to move the cold air around moreso that actually work directly with the evaporator.
The defrost timer can make noise. In most refrigerators it’s just a very small motor driven by a handful of small nylon gears. They can make some racket when they’re starting to grind.
The defrost cycle itself can make noise. It tends to be a bit louder. Usually a combination of metal expanding as the heaters turn on and they themselves heat up and the coils around them get warm as well as the sound of ice breaking/cracking/snapping. It can be rhythmic/deep. During the defrost cycle, all the fans and the compressor will be shut down, this is important later.
Lastly (off the top of my head, in the middle of the night), during the defrost cycle, you may hear water dripping into the tray under the fridge. Whether it’s just dripping onto an empty plastic tray, dripping onto water that’s still sitting there, overflowing and dripping onto the floor or the drain is clogged and it’s just dripping and stacking up inside all depends on other factors.
Oh, one last thing, if you have an ice maker, they can make all kinds of noises as well. Between filling, flipping ice into the bin, a quick warming of the tray to loosen the ice etc.
One thing to listen to is the next several times the fridge makes the noise, see what else is going on and try to notice a patter. Is the fridge running when it happens? Is it off? If you have an ice maker, is it doing something etc? One time doesn’t mean anything, but if you find that every time it makes this sound it’s making ice or just about to turn back on or any other pattern we can work with, it’ll make troubleshooting a lot easier.
PS, see if opening the door stops it? If it does that may (or may not) rule out a bunch of things very quickly.
PPS, I see you have no ice maker, so ignore all that. Also, if you don’t have anything perishable, a quick thing to try is to unplug it for 24 hours or so and leave the doors (fridge and freezer) open. Plan to put towels in and under/around it. That rule out anything that has to do with ice build up. That is if there’s any ice build up in areas that could be causing issues (like hitting a fan), it should melt in 24 hours.
WAG, it sounds like a motor that’s unbalanced or has a bad bearing. But there’s at least three motors. As someone else stated, the compressor motor is easy to access and vacuum off. It’s also an easy way to see if you have mice.