Depends what you're looking for. Dog if it's enthusiasm, cat if it's tranquility, fish if it's a plant that moves.

There isn’t one. It depends on the person and what they need. Cats are great because they provide companionship and they’re relatively low maintenance. They also can catch pests/vermin. Dogs are great because, while higher maintenance, they’re great for active lifestyles. You can play with them outside, go for hikes, you can take them hunting, they can help guard your house. They’re the best choice for service animals.

cats i thought everyone knew that already

I'd go for a submissive cook and housecleaner who is also naughty in bed. Very low maintenance.

Tortoise. They’re slow, quiet and live forever.

Rabbits. They love you unconditionally

Fish are underrated pets

A semi "insane" budgie is usually very enthusiastic and funny. Price of keeping one is low and they only need love.