Is there a website which gives examples of designed PCBs to learn from them

I want to understand a few things by looking at real worl PCBs.
For single sided boards, how are power and ground planes arranged? How do signal traces route through these planes? Besides, what there are analogue and digital power and ground planes, what then? How is this done for two sided boards? Does it make a difference whether we have surface mount of through hole components? Do we only really need ground plane but no VCC plane?

For two sided boards, are only surface mount components possible to use? Also, since the ground plane is on the bottom, does this mean that a via is used to connect ground to surface mount components in them?

Finally, how would things change if we have 5V digital supply as well as 3.3V digital supply. Will they both have the same ground plane?

I understand that my questions are too numerous. Is there some resource that you recommend I use for this purpose.

If V+ to Gnd is coupled with low ESR RF caps and electrolytic, pwr plane is same as gnd plane at RF. but if high current spikes, you need low L tracks ie. fat and low R for IR drop. Thus in gigh power apps 1sided boards and many multi layer boards use " busbar" components with thru hole pins to distribute power and jump signal tracks.

Small or very fast signals benefit with interleaved ground tracks if no ground plane. Just beware that slots and gaps and untwisted paired cap dumps or inductive kicks generate EMI so CM rejection or crosstalk isolation is a design factor.

Active guarding is used instead of ground for mV signals on long tracks or wires. Differential in or out balanced used when dealing near stepper motors or SMPS etc.

Layer reduction for lowest lost in high volume takes these advanced design skills where adding more layers is easier.

for reading on EMI in general, the guru of EMI control is Henry Ott since the 60's. Find his book.

goto protoExpress Sierra circuits site for technology white papers on boards.

I have a feeling that people are growing tired from my questions here. I am learning a LOT from here. So I just keep coming back. Once I have a (personal) project up and running, I will bring it to this website as well.

What will one do with the GND plane if the board uses surface mount components as well as through hole components

Vias have inductance around 1.2nH , use as many microvias in parallel as required.

https://www.ti.com/lit/ml/slyp173/slyp173.pdf

The "groundplane" will often (in the case you mention) be either the bottom layer for a 2 layer board or a complete inner layer(s) for multi layer boards.
Research "slots in groundplane" to find out more about good practice with them.

Research "Thermal relief" for PTH component use (you will also find it used on SMT components).

As for growing tired - if you ask a simple question with an explanation that would require a basic answer then no we will not grow tired, those of us that know stuff often like to pass it on to those that do not.
If you ask (like someone else just has) for major topics to be explained to them which would requires a complete essay to answer each one - then yes we will get tired.