A very broad question. I teach sound design for games at the university of the arts in Zurich, Switzerland, and from what I’ve learned with my students is that sound is something you have to learn and experience. It’s a huge field with many different parameters to tweak, and nothing goes over your personal experience.
Because you cannot describe sound. You can only hear sound. It’s like trying to explain a person who’s been blind the whole life how blue or red looks.
Sound design and foley is about tapping into your experience. Thinking about the sound. How should something sound. Big, small, nervous, repetitive, relaxed, digital, sci-fi, natural, wooden, metal-like and then trying to translate that into sound. You have to record sound in the desired quality, have solid mics, decide from where you want to record your sounds. What distance. And then, if you do the foley sounds yourself, the performance is absolute key.
Every sound you make is like an instrument. You can play an instrument gently, or aggressive. A violin has many different playing styles or articulations. Legato, staccato, marcato, pizzicato. And so has everything you record a performance. Even simple things as footsteps. You can walk fast, run, stroll. And you can hear it by the sound the shoes do. There are many different shoes, too. Sneakers, boots, bare feet. Everything sounds differently. So the original performance of what you record is absolutely key.
You don’t have to create your own recordings, though. There are tons of people you have the equipment and like doing that stuff. Look for great sound libraries such as the Hybrid Sound Library by ProSoundEffects.com, or go to ASoundEffect.com where there are tons of great indie sound libs that sound great.
Then, once you have your source material, you enter the world of digital plugins. You cannot make a great rich deep sounding trailer voice out of a recording of a women. You cannot make a great sounding explosion out of popping a plastic bag. Plugins can only shape the sound that’s there. That’s why I said the initial performance is key. But you can shape the sound. There are plugins that alter the pitch of a sound, plugins that chop a sound up into small parts and re-arrange them, that turn the volume up and down very quickly or layer a sound at different pitch together.
And here is your experience that comes in. You have to play with your plugins and then remember what they do and how they can transform a sound. Then, if you want something sci-fi, you turn to a handful of plugins that you know could do the job as you heard it before. Or something alien.
And as to your questions. Synthesis plugins are great for creating beeps and chirps, some have effects racks that you can route external audio through (your recordings). You can use deep sine waves to give a sound a sub-bass rumble.
There are hundreds of cool plugins, and many of them mangle sounds in a crazy way. There are no standards. There’s only your experience. You have to play with them and see which ones suit you and you think are intuitive to use. Plugins that alter pitch, slow a sound down or up, distort a sound or compress a sound are the go to bread and butter plugins. Then there are vocoders that “transfer” a frequency spectrum from one sound to another, granular plugins that chop up a sound into thousands of little pieces, delay and reverb plugins and so on and so forth.
I personally don’t use Kontakt as I find it hard to use. And I wouldn’t use it for one-off sounds like an explosion as it doesn’t give you any advantage in my opinion to mangling the sound in a DAW. You have more freedom in a DAW. What is interesting is the application for repetitive sounds like footsteps. Load a few variations of recorded footsteps into any sampler, randomize the volume a little, randomize the pitch with every hit of a key and every step will sound slightly different. Then you can quickly sync your footsteps to picture by playing a MIDI keyboard. If you miss a step, you can easily move the MIDI note around. I found that to be a great use and fast workflow for a sampler. But there are dozens of other techniques.
Everybody works differently so I’m sure everybody has their own opinion but maybe I could guide you the way a little and show some possibilities.