Okay, by faeries you mean magical creatures or just “fairies”?
And the advantage of writing fictional stories is that you can do anything. No one will judge you as long as you don’t bring up something related to reality. Like you can’t introduce traditions which aren’t usually practised on a festival in real world. But you can take examples from the reality and make similar traditions and cultural practices. For example if you read the “Throne of Glass series” by Sarah J Maas, you’ll find there are several holidays and festivals which are actually like the ones we have in reality but have a different name, purpose and a few extra details to make it creative.
I hope I didn’t confuse you further. 
The hardest part of writing a fantasy story is coming up with names. I’m facing the same problem actually. Naming places, characters, coming up with last names, etc are really pain in the *ss. There are many name generator sites which are sometimes may give you stupid names but if you’re lucky you may find what you are looking for. Besides, you can ask in the Episode community. The amazing people here are really helpful and creative and can help you come up with names and all.
Coming to fantasy creatures, I usually use the fictional creatures we all are already familiar with, such as dragons/Wyverns, hippogriff, unicorn, pixies to name a few. If you come up with new creatures try naming them based on their appearance or character.
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