In fantasy, there are several well-established races, nations and factions, that spread across multiple universes. They share identical or very similar characteristics in every universe and are generally easily adopted by the players/readers of the story. I believe, these are the 6 most iconic and most wide-spread fantasy races:
- Humans - often divided into several nations, kingdoms or factions, but always resembling some medieval human nation from the real history
- Elves - most often either as the more civilized version (high/sun elves), or a wilder version (wood/night elves)
- Drow - or dark elves, or other iteration of a sinister underground race
- Orcs - together with goblins, trolls, ogres, etc.
- Undead - maybe not really a race, but definitely a faction.
All of those races have several tropes that can be easily connected to them (human knight, elven ranger, dwarven miner, orc raider,...). Is there a water-based or amphibious race/faction that has comparably strong roots in several fantasy universes, is generally known and can be easily associated with one or several tropes? I believe, the naga or the lizardmen may be the closest, but both of them are considered a "secondary" race in all universes I know of.