Here are some popular sites:
See related links below.
Toontown, virtual pets world, and marapets. Thats all I can think of virtual pets things.
Neopets and IcePets are two popular and ever-growing sites you might like to try. See related links. :)
There are many different virtual desktop pet downloads. Both Microsoft and Apple have their own applications stores where downloading virtual desktop pets is possible. There are also many online sites where desktop pets can be downloaded.
You can create a virtual pet site for free on myvirtualpetsite.com
You don't....
It sounds like you want a clone of Foopets. There are a lot of good sites out there that let you breed your pets but no one has interaction like Foopets does currently. If you want to breed wolves, try Wajas.com. If you want to breed cats, try Felisfire.com. Both are good sites.
guffins.com-virtual pets & pet games.com
Sims 2 and 3 pets
Cork, tile, or hardwood flooring is best if you have pets and kids.
I dont fully understand what the question is, but a list of virtual world sites would include Subeta, a newer one called Menewsha, Sylfe, similar sites but with pets like Neopets, Marapets, Powerpets, or even simply dating virtual sites, like IMVU, which requires downloading of the actual game.
Webkinz?
Yes, they are very good cats, especially with kids and other pets.