So for starters we can just start throwing all relevant tech and applications for that tech together. And we'll arrange it in a pretty way and get it pinned to the top of this thread or something eventually.
So DACUS is good for chasing people's wakeup rolls when they're on platforms. It's one of the most obvious applications but still does a lot of work. A more seldom tried application for it is tech chasing, and while it can provide good results for that, it has limited utility when chasing at low percents, and has to be too meticulously spaced against most characters as the DACUS will travel further than their roll. As a little aside to using DACUS to chase rolls, I've been trying DACUS to finish up/ connect combos that I usually couldn't as its particular speed and distance can sometimes make it the best way to pursue the opponent. Probably not the best use, but just food for thought.
Wave Landing aerials is quintessential to Ganon's ability to keep up with a lot of characters movement, and through that keeping up, stay threatening. He can WL short hop Bair and short hop Uair, but in both cases the move needs to be started a bit early into his hop. Using this during combos is nice, but the less obvious application is using this in the neutral as it lets you fill parts of the stage with your fatty aerials while surging towards or away from your opponent upon landing. A good trick to apply to shield happy opponents is short hop Bair > WL behind them > grab/ jab/ footstool. Since this can be used in the neutral to give Ganon unexpected bursts of movement, it works well in conjunction with the Arty vortex, as you can alternate between which aerials you're putting out and what you do when you land.
The Arty Vortex is much talked about and held in some level of reverence but it's really a pretty simple trick, though in this case simplicity=effectiveness. For those of you who haven't seen it or don't know quite how to perform it, you short hop and Neutral Air right before the apex of your jump, and then fast fall as soon as possible. If performed correctly they'll auto cancel when you hit the ground, letting you immediately act out of it. The idea is that you're active and attacking constantly to make your opponent not sure when you'll act. If they try to rush you when you're doing it you can Ftilt or shield upon hitting the ground. If they hang back because they're not sure what to do, you can dash forward and grab or flame choke. It isn't unbeatable though, and people who know of it, or are familiar with Ganondorf will be able to work around it, which is why I suggest mixing it in with WL'ing Bairs and Uairs, as it'll keep your opponent on their toes while trying to counter it, and give you the same result of sitting in a constantly churning vortex of spite and planning.
The extended Fsmash (we should brainstorm a name maybe) doesn't need that much of a write up because it's a neat technique but not comparable to the last few techniques in multiplicity of application. Simply put, the extended Fsmash is a surprise poking tool that can be used to slap your opponent harder than they might expect to punish a mistake, or simply tag them with it for not expecting it. As mentioned earlier it has the strange property of dodging some attacks as it is a step back and a step forward to attack.
Now footstooling is used by very few players, but has a really crazy amount of utility, and opens up options that you wouldn't normally have access to in combos and shield pressure. First and foremost footstooling can be used on a grounded opponent to make them momentarily stumble, or if they're shielding, drop their shield for a second. While this stagger doesn't give you enough time to combo into an attack, it's almost always unexpected and might flumox your opponent enough to land an attack, or at the very least position yourself for some other setup. The most obvious use of this is footstool > Dair as a combo starter, while a less trafficked use is footstool > waveland > grab. One setup I've incorporated with modest success is Bair > WL behind opponent > footstool > Nair behind opponent > grab. This assumes that they shield the aerials you use, but if they do it is tricky as hell and highlights Ganon's more interesting tech while not necessarily explaining to your opponent what was done or how you would counter it. While footstooling grounded opponents is seldom touched, I've seen aerial footstool used about three times in all of the P:M footage I've watched. While it has less obvious application, I've found that it can lead to some setups that Ganon would have a hard time placing before. For instance, Ganon can place people on platforms mid combo to set up for biased roll chasing. The setup I use the most for this is (when below a platform) Dair > footstool. It can also be used to mess up peoples tech timing as the falling state it puts you in is a very particular speed.
I'll write more as it occurs to me and I encourage other players to kick in knowledge as they please, and help edit/ adjust what I've written up based on their own experience.