I havent been here in awhile so my knowledge could be a bit low

People sell Essences in the trade broker
I think you have a low percentage of getting an essence when defeating a wild sylesti?
I know for a fact there is a low percentage of getting them while nurturing sylesti hatchlings and egglings

Naturally the diamond shop

I think thats it??

okay I ask cause i did find one early on and made a vulynix but im not sure if thats something thats supposed to happen or not

You can very rarely find essences while fighting, but the chances are extremely low. Pretty much all the ways except the diamond shop and buying from others have very low drop rates.

I would not waste your money on low level nets. In my experience, the chances of a low level net actually catching a pet is crazy low. Especially since money is tight at low levels. If you are looking for pets for breeding projects or to make mission pets, you are much better off using the advanced search. At least that way you are guaranteed a pet for your money.

advanced search?

At the left side of the page near the top there is some blue writing that says Advanced Search. This will take you to a screen where you can either search user or search pets (pic of Griffi). There you will have all sorts of options on how to search. I think this link will work...
https://www.sylestia.com/search/?type=1&val=

Just be careful you do not go too crazy and get so many pets you can not feed them. :-P

yup ^-^ also is there a way to earn diamonds naturally?

Nope they are a RL cash purchased, you can exchange gold for diamonds though.

Guide to Generator Essences here, ways to obtain essences covered in section 3 on page 1

Adding onto what the other two said, you can also exchange gold for diamonds in the Currency Exchange, and the Winter Festival advent calendar gives ~200 diamonds each year, I think.

thanks!