Paladance has the reason spot-on. How many pets have you rated, and when was the last time you adjusted your ratings to reflect current balance?
A lot of people will have rated theirs quite a while ago, so changes don't get reflected. Any "popular vote" list over a long period will have some irrational skewing or bias by time.
I really feel guilty about how few pets I've rated.
It's just awkward to do hundreds one by one. I should figure a way to get the data in more efficiently than thinking "Um, Albino Chimaeraling? S/S or P/P? um...."
I added up some numbers here: https://www.warcraftpets.com/community/forum/viewtopic.php?f=3&t=16391&p=131412#p131412 which I expect is as good a list as you will find for the beginning battler doing PvE. PvP tends to use different pets, because speed and trickery are more useful there, so PvP would have a different list.
Hm. Comparing that Top 20 with the Top 21 (those that got 3 or more uses in the strats) from wow-petguide.com. 10 are in both lists. Of the Top 20 here, I would say that
would earn an honourable place in a list of Top PvE pets. Aranesh would be reluctant to promote a strat for Lil' Ragnaros, since it's a shop pet, and Kun-Lai Runt is a bit breed-dependent for that list as well, but they're both very strong. Magical Crawdad could replace Emperor Crab in a lot of PvE strats, so that one is pretty legit, with the advantage of not depending on breed, but it's a little hard to get / expensive, so people would be reluctant to use it in strats meant for a wide audience.
That leaves these 4 as questionable in a Top list
Pandaren Water Spirit
Son of Animus
Xu-Fu, Cub of Xuen
Xu-Fu's ratings here are probably skewed by how people got him. I was proud of that, and I'm sure most felt the same way. Graves was hyped to the heavens at one point. PWS was half of Howlbomb, and the ratings haven't caught up with the nerf. That leaves Son of Animus as the only one I can't account for.
So what is not in the Top 20 that is in wow-petguide.com 's strats? Well, yes, Teroclaw and Ikky, largely because they are newer pets, but also entries like "Any Moth", "Any Snail", "Any Fox", "Any Rabbit". And this probably reflects that fact that no specific species can be identified as "Best". So when you make a Top 20 list, which species of 357 speed rabbit should you include? I suppose in a curated list, the totals for all pets with the same moveset and stats could be totalled, to create an entry "357-speed Rabbit", but this Top 20 lists only defined species, not sets of species.
If you go to
and search for Battle rating > 3 Stars
and then click to Sort By Battle Rating
you will see that the Anklerender actually comes in at #22, and Teroclaw at #23
(and, oh my gawd, Micronax has a Battle Rating of 4.05, with 10 votes, even though nobody in the world has it yet. I can't imagine a better example of why some of the votes are crazy. Who would do that?) I'm glad that the Site Top 20 puts a cut-off on the number of votes needed for inclusion.
One final thing: 20 is a very arbitrary number, and there is a set of I'd say 30-50 pets that is kind of a core group. If you have those, you can do pretty much everything in PvE. So saying that the Scourged Whelpling is #20 and the Anklerender is #21 in that set is not a distinction that really means anything. (But we all love Top X lists.
See also this thread, asking the same question https://www.warcraftpets.com/community/forum/viewtopic.php?f=3&t=16578