Project Apollo has an amazing list of classic clichés we find over and over in ebery single RPG. My favourites are these:

6.- Single Parent Rule
RPG characters with two living parents are almost unheard of. As a general rule, male characters will only have a mother, and female characters will only have a father. The missing parent either vanished mysteriously and traumatically several years ago or is never referred to at all. Frequently the main character’s surviving parent will also meet an awkward end just after the story begins, thus freeing him of inconvenient filial obligations.

18.- Crono’s Complaint
The less the main character talks, the more words are put into his mouth, and therefore the more trouble he gets into through no fault of his own.

21.- Aeris’s Corollary
Just as the main male character will always use a sword or a variant of a sword, the main female character will always use a rod or a staff of some sort.

40.- Zelda’s Axiom
Whenever somebody tells you about “the five ancient talismans” or “the nine legendary crystals” or whatever, you can be quite confident that Saving the World will require you to go out and find every last one of them.

140.- Law of NPC Relativity (Magus Rule)
Characters can accomplish superhuman physical feats, defeat enemies with one hand tied behind their back and use incredible abilities — until they join your party and you can control them. Then these wonderful powers all vanish, along with most of their hit points.

Check out the full list, it´s long but a really fun read.