>>57594266i'm not sure if I can even properly reply to this thread if you're going off of competitive/PVP because all the mons I like all support playstyles I like using for those given mons
for playthroughs I'd say it's the fletchling line
since its best STAB moves via level up before the endgame of a typical official game playthrough are flame charge (at 38/39 for fletchinder/talonflame, respectively) and acrobatics at level 44; you have to use peck and ember until then
not counting brave bird since it's at level FUCKING 64 and by the time you reach that level you have almost nothing left to use it on besides the postgame
you're forced to use TMs to give it actually usable STABs past the early game
at least gen 8 gives the line actually reasonable levels for its level up moves but I don't own a switch and I don't really remember playing any (good enough to be worth mentioning) fangames where smogonbird has its gen 8 learnset
my guess for why it suffers early gen level up learnset syndrome (despite being a gen 6 mon) is that someone at GF was scared of making a potentially good early birdmon within the context of playthroughs after seeing Staraptor appear on half of all sinnoh teams because it got close combat upon evolution (level 34)
also no i'm not counting gale wings because let's face it you're not realistically getting hidden abilities in a typical playthrough without specifically looking up how to get them, or trading mons over from other games (and at that point you might as well trade over literally anything)