Pepsi ranks at #861 with 137 entries, registered as gender-neutral. The name is the soft-drink brand, full stop — there is no etymology to chase beyond a 1898 Caleb Bradham trademark for a digestion-aid soda fountain syrup. On a pet registry it slots into the soda-and-snack-food cohort, alongside Coke, Soda, and Bubbles.
The brand-name food cohort
Pepsi sits with Oreo, Cocoa, and Soda in the deliberately-snackable register. Most Pepsi pets are visually black-coated or have the deep brown-black of the can color, and the naming logic is direct: the dog or cat looks like the drink and the household says so out loud.
Coat-color pick
The name lands hardest on dark-coated mixes, black Labs, and short-haired black cats. Two syllables, front-stressed (PEP-see), with the bright crisp P-opening and bouncy ending — easy recall, hard to confuse with command words.
The counter-reading
The honest concern: the name is locked to a beverage that may or may not still exist as a brand in 30 years, and it reads as casual rather than considered. For households who like that, it works. Browse pet names for related food-brand picks, or check the unrelated human registry — minimal traffic there.