When using the code of the Led Effects All in one project, you could modify it to actually do this.

You can modify the void loop() to make a random selection. 

Modify this part:

void loop() { 
  EEPROM.get(0,selectedEffect); 
  
  if(selectedEffect>18) { 
    selectedEffect=0;
    EEPROM.put(0,0); 
  } 
  
  switch(selectedEffect) {

to this:

void loop() { 
  selectedEffect=random(18); // assuming there are 18 effects
  switch(selectedEffect) {

The entire EEPROM part has been removed and has been replaced by a random selection (0 to 18).

Now the random function of the Arduino is most certainly not the best random generator.
To improve the randomness, you can add the following line to the void setup() function;

randomSeed(analogRead(0));

Hope this helps ... curious to see what the end result will be 

That's hot... it kinds of work, but would there be a way to not make it random.... just so it execute the next pattern everytime to turn it off then on? And I had to remove every break; in the code so it sticks to the same pattern cause it was randoming from one to another in a constant loop.

So, if there was a way to instead of making it random, just a pattern after another.... I guess we would have to store this information for the next power on? is that possible?

You're right, I made a little boo-boo there.

Change void Setup() to:

void setup() 
{
  FastLED.addLeds<WS2811, PIN, GRB>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
  digitalWrite (BUTTON, HIGH);  // internal pull-up resistor 
  // -> remove the attach interrupt line
  // -> and add this:
  EEPROM.get(0,selectedEffect); // get previous effect
  selectedEffect++;             // increase by 1 
  if(selectedEffect>18) {       // if the new value>18 then reset value=0
    selectedEffect=0;
    EEPROM.put(0,0); 
  } 
}

Modify the original loop (keep the breaks in there!), so it looks like this (disable the EEPROM functions in the loop()):
Note: you'll have to put the "break" calls back again.

void loop() { 
  // EEPROM.get(0,selectedEffect); 
  //
  // if(selectedEffect>18) { 
  //   selectedEffect=0;
  //   EEPROM.put(0,0); 
  // } 
  
  switch(selectedEffect) {

And finally you can remove the void changeEffect() function.

Wasn't working, was always playing the Strobe pattern, so I made a modification and seems to work well now, here is what I added to your code:

void setup()
{
  FastLED.addLeds<WS2811, PIN, GRB>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
  digitalWrite (BUTTON, HIGH);  // internal pull-up resistor
   EEPROM.get(0,selectedEffect); // get previous effect
  selectedEffect++;             // increase by 1 
  if(selectedEffect>18) {       // if the new value>18 then reset value=0
    selectedEffect=0;
    EEPROM.put(0,0); 
  }
<span style="text-align: initial;">  EEPROM.put(0,selectedEffect); // Write new effect value to EEPROM
</span>}

I'm repairing my Hot Tub currently, should be running again this week. I'll make a video with the light color effects, will be nice! hehe! Cheers man, thanks for the help, it's awesome!

Awesome - glad you got it to work 

Would you mind posting the final sketch? Maybe others can benefit from it as well.
And ... I'll be looking forward to the end result! 

So here is the .ino file of my first version sketch for my Hot Tub. I will be modifying this to remove the "no compatible hot tub" patterns and replace/add new "hot tub friendly" light patterns. 
I already replace the "Case 3" (Halloween Eyes) with a custom one that fades slowly from color to another covering all spectrum. I like this one, it's relaxing.
Thanks to Hans, can't wait to try it in the Hot Tub.

Awesome! 

Also note; this line can be removed from the void setup();

digitalWrite (BUTTON, HIGH);  // internal pull-up resistor

It was used for the toggle button, but you do not have a use for it anymore .

Thanks for posting the sketch! 

Here's the result: https://youtu.be/u-xAkMBmfKM

I added a credit link to this thread in the YouTube description. Thanks again Hans!

Nicely done!!! 

Glad I could help you out with this - it looks pretty cool! Now I need to go get myself a hot tub