Prestige ranks is a set of ranks immediately available after ranking up to Cod, starting with Prestige Chicken. These are not for the faint of heart, they are very difficult.
Since Prestige ranks are meant for discovery, there are very few things publicly known about them and they are rarely discussed (and not encouraged to be discussed) publicly. Once you obtain Prestige Chicken (and if your discord role is linked to your in-game rank) you'll gain access to #prestige-corner channel in discord where people can openly talk about the topic.
Some stuff we know:
There is a shop category in /shop that is only accessible to Prestige Dragon and higher
One of the rewards for Prestige Chicken is a Builder's Wand
You can summon the dragons Margareet, Meatloaf, and Potato at different stages of Prestige
Occasionally people Prestiging open a Crystamae Crate
They use bits for crafting recipes only available during Prestige ranks
People who are Prestiging visit /warp EliteCrafting