Link to the guide; Pet Jewelry & How to acquire or create it
There are 4 types of pet Jewelry.:
Chains (leash/ choker), collars (chaplet), foot rings and nameplates (accessory).
The best of these 4 (1 of each kind) can be found for sale in the regular item mall. But, these 4 items are for level 100 pets so, only fully trained pets can wear them.
The next best ...also for level 100 pets...
the Dragon Collar (chaplet), Dragon Foot Ring, Silver Accessory (nameplate) and Tiger Choker (chain) can be bought at various municipal ministers by the guild officers of the guilds that own the cities and they should then be able to sell them to you.
see this guide for locations;
Guild owned City products (commercialization degree)
You can get all levels of chains (leash/choker) and nameplates from Exotic Pet Trader maps...
Chaplets (collars) and Foot rings must be player made ... or just wait until your pet is lvl 100 and buy the IM jewelry.
see post 3 of pet jewelry guide or use this link; Exotic Pet trader info
*warning* drop rate for higher lvl jewelry is low... and you only get 1 map per day. I use to save up 4 or 5 maps then go find them ... which is easy as they are in the same spots every time (see linked guide).
ps. btw you can drill pet jewelry with basic stones (add attack stone etc..) but you can not use refining items on them.