to get the rocket essences go to rocket reef and shake trees that have rocket essences.
there are no elegant essences
Angry essences are found by running on the treadmill.
you dig for them & mine them
Everywhere. You can find essences everywhere on My Sims Kingdom. You can dig or mine or shake trees and pull dandelions. You can get he emotion essences by going up to someone and clicking "Be Mean" or "Be Nice". To get the scary essence, you have to unlock Rocket Reef and hook up the ride in Vic's training place. You can also got to Spookane (also need to unlock).
I love the Sims kingdom too and all you have to do is follow what you have to do in your missions
In a place around that area.
you need the 4 raindrop essences and the gold planet essences
You need the bubble essence
go to the ski lift and use the extracator
Press R and you will see the list on the top screen.
You can usually find all essences when you pull up weeds. You will need patience but it should work.
You have to complete Rocket Reef(when the rocket is launched).