These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Darkhorse: While more-or-less each game has its own darkhorse, there are a few recurring monsters/summons that get a lot of love from the fandom:
Tonberries are generally well-loved for looking adorable for such little killers, not to mention often giving decent rewards for (managing to) defeat them.
Cactuars
Chocobos and Moogles, but generally Chocobos are prefered (as they can restore all MP, and allow you bypass monster you don't feel like fighting).
Amongst Summons, Ifrit and Shiva are this, despite being more or less useless against enemies that are effected by their element.
As of late, Flans. Especially the XIII-2's incarnation of miniflans.
Growing the Beard: It is generally agreed that the series has done this, but there is no general consensus to when this happened, being the subject of massive Flame Wars. General consensus is it happened somewhere from IV to VII. Each game in that span, in their own ways, radically improved upon the gameplay, plot and/or characters compared to what came before.
Also, people can't seem to get straight who does what in the production. People often blamed for the direction of a game or the story are actually the character designers. (Granted, this is not assisted by a fairly prominent example of a character designer moving up to a director's position where he did have more control over game and story direction.)
Scapegoat Creator: As mentioned above, some people tend to blame the wrong people for the direction of the games. *
Nomura is (usually) merely the artist, and not always even the head artist.
The Scrappy: There's usually at least one character per game that nobody wants in their party, no matter how good they are.
True Art Is Incomprehensible: Pick any game from the Final Fantasy franchise. Good luck trying to follow its plot. Even the original, with the most lightweight plot of all, manages to be confusing with what it has.
I and III don't especially have protagonists beyond being Heroic Mimes
, and XI and XIV are both MM Os]]) femaleprotagonists; and even that is debatable because both of those games unusually share the spotlight pretty equally between party members, making said female mainly just a mascot.