What is the most populous race in the Alpha and Beta quadrants?

Question

In the Alpha and Beta Quadrants we encounter many different alien races. Was it ever commented on which race had the highest population? We know both the Klingon and Romulan empires had fleets to match the Federation, comprised primarily of their respective races, while the Federation incorporates many different alien species.

Out of the alien races we know of, which is the most populous in these 2 quadrants?

Would like specifically looking for, what we could say as sentient lifeforms(klingons, humans, vulcans, ect).

But tribble or other answers welcome if you have accurate counts

Answer 1

Echoing my answer here

Geoffrey Mandel's "Star Trek : Star Charts" (which isn't generally considered truly canon but was at least 'advised on' by Senior Trek Designer Michael Okuda) indicates that the Ferengi homeworld (Ferenginar) has a popuation of over 78 billion:

Of the Federation worlds, Andoria has a population of 38.2 Billion, representing some 3.2% of the total population of the Federation.

By comparison, Vulcan has a population of 6 billion, Romulus has a population over just over 18 billion and Kronos (Qo'noS) has a population of just under 3.5 billion. This of course doesn't take into account the relative sizes of their empires/colonies. For example, there's a mention that during an alternate timeline war with the Federation, Klingon casualties may have numberered into the tens of billions.

---

Purely as a matter of interest, per this excellent answer we can reasonably assert that the Human population (including Earth and its associated colonies) was anything between 12 and 20 Billion in the same time period.