IMO...
Pills - Absolutely not
Creams - No way
Surgery - Risky
Exercises - Moderate benefit
Pumps - Temporary Increase
Traction Tools (Male Edge/Andro etc) - Permanent Gains with dedication
You only need to look at uses elsewhere for each method. We know Pumps work for a temporary increase, the evidence is able to be found on Google.
Stretchers like the Andro and Male Edge are based on proven science. .
So, I'm afraid if you really want a bigger dick, the only way to make permanent gains is through investing a little money and a lot of dedication. There is no quick fix.
I agree with you with exception to Exercises, Pumps, and traction.
Pumping gave me the most size increase, permanently. I haven't done much Jelq, but the many that have tried it either by BigAl's source or Thunders place have seen improvements.
I have noticed with my Quick Pro Extender, I tend to hang lower than I have ever done before. Erect size is slightly larger.
PE results vary from person to person. Like others have said already, do your research, and spend a little cash on either a pump or stretcher.
You can also try the stretching exercises - that information is free.
The rest, stay away from. Unless it's something medically prescribed from your doctor for a specific purpose... save your money.