What frequency of sound waves produces the most vibration The name of the question is rather contradictory and counter-intuitive since sound is produced by vibration. However, very low frequencies around 32Hz and receding are bass. 
From what I have read online, you can feel frequencies below 20Hz which is what we normally hear, yet you can hear as low as 12Hz while amplifying very high frequencies (above 20k Hz? I'm not an expert). So again, which frequency(ies) should I amplify in my equalizer to achieve this effect?
 A: I think you mean: for a given loudness, which frequencies involve greater physical movement, high frequencies or low? And that is simple - the lower the frequency the greater the amplitude of the movement. Here's a simple demonstration. Take the grille cloth off a speaker with a woofer. Play music through the speaker, something with sustained notes like organ music. Watch the surface of the woofer. For very low notes you can see the speaker move. It's true that the woofer only handles the very low notes, but if you use a speaker with, for instance, a woofer and a tweeter only, the woofer handles quite a range of frequencies, although not as great as a system with more speakers.
In general, all else being equal, a vibrating surface which has a fixed excursion (length of motion) will produce sound pressure levels (basically, loudness, although the perception of loudness gets complicated, and varies somewhat with frequency) which are proportional to the square of the frequency. That is, if you double the frequency you quadruple the pressure levels.  
