Pets

Enabling old pet models
Enabling of the old pet models can be achieved either by entering configuration, or by making sure that this line exists in your eqclient.ini file

UseLuclinElementals=FALSE

Adoptable pets
From the July 6, 2016 patch message: Lynea the pet collector in the Commonlands will purchase your excess adoptable pets for a unique currency. You can buy a random discontinued pet from her using this currency.

Illusions
Since the November 16, 2016 patch, if you own the Familiar Key Ring feature, any illusion spells on summoned pets will persist when you zone.