Find a cool word, change the first letter, add a better ending to it.

Guardian -> Xuardian -> Xuardyen.

Something like that. And suddenly... Xuardyen plays: Somerandomgame (Episode 1)

You can try spinxo.com.

Just enter in some helpful keywords and it generates YouTube, Instagram or Twitter usernames for you. Hope this helps.

Think of What you like and Make a Name Out of it.

It should be at least 2 and at most 4 Syllables (Is that how its written?)

And try and Think of Something Catchy. TheAceOfGaming is too long and not very easy to remember.

This is what I did:
I thought of what I like: Watermelons
Spain
Then I added in my Nickname for Youtube: Ace

So I came up with: Channel-Name: ElMelonAce
and Name: Ace or El Melon

I think its pretty catchy!

(My Channel isnt finished yet and I am having some upload problems, so its not ready yet)

Best channel name would be one which is original and can easily be remembered.

So avoid stuff like XxXMLG_Failsc0peXxX and Pewbuscus etc. , both are unoriginal and expect haters for the latter.

A friend of mine would always close his eyes, open them, first thing he saw was the first part. Picked a number between 1-100, and then repeated the first step. He's ended up with some interesting usernames xD