true but logically speaking that kind of falls in the envelope category only because it has to detect the nuances from the guitar. which you can typically find on the net a simple flow chart for standard pedal arrangement. anything that is a filter or envelope type device needs to see the pure guitar signal. ie good harmonizers envelope filters/followers wahs [wahs are more subjective some people like them after everything else] gain devices boost od distortion etc.. modulation fx then time base fx.
there is no set rule but common sense will tell you if your trying to use an effect which drastically alters the sound as much as an acoustic simulator really anything modeling at all should go first. but then again you get some cool sounds by not doing it in any set pattern. i have an on board oscillator that i use on a push pull switch in my guitar and it goes before everything, but it produces a nice fat rectangle wave so i have to pad it down before it hits the amp. but i also have a boss feedbacker clone where the dry signal come in but doesn't leave. so only the effected sound comes out with a cool mod to track the input i can take the input signal and trigger the foot-switch to hold the effect in the octave mode so slightly after each pick attack a variable swelled octave rings out. so all you hear is the effect. comes in handy when your playing acoustic or classical and have a haunting lead come from no where. so in essence it all depends on what sound you are going for. this is why i have three seperate pedal boards