the lord of the rings - Who were the greatest archers in Middle-earth, according to Tolkien?

I've read about quite a few prodigious archers in Middle-earth: Beleg, Legolas, Rangers like Aragorn (not sure about this one) as well as other Men of Gondor, Easterlings (not sure where I've seen anything about them, actually) and Bard.

Main question:
Who (according to Tolkien) was the greatest archer from each race?

Bonus question:
Was there a single archer (of any race) who Tolkien esteemed above all others?

Answer

Elves

The greatest Elf bowman appears to be Duilin of Gondolin, an Elf-lord of Gondolin and chief of the House of the Swallow

In his "Unfinished Tales", Tolkien specifically refers to him as being a soldier of impeccable physical prowess and has this to say about his abilities with a bow;

Now the folk of the Swallow bore a fan of feathers on their helms, and they were arrayed in white and dark blue and in purple and black and showed an arrowhead on their shields. Their lord was Duilin, swiftest of all men to run and leap and surest of archers at a mark.

Beleg Cuthalion(A.K.A. "Beleg the Archer", A.K.A. "Beleg Strongbow") is also repeatedly called out as being an exceptional archer and possessing the ability to fire arrows great distances:

Moreover Beleg the Archer was great among the people of Doriath; he was strong, and enduring, and far-sighted in mind as well as eye, and at need he was valiant in battle, relying not only upon the swift arrows of his long bow, but also upon his great sword Anglachel (needed only by an archer because the orcs were so many). And ever the more did hatred grow in the heart of Mîm, who hated all Elves, as has been told, and who looked with a jealous eye on the love that Túrin bore to Beleg. _{^{The Children of Hurin}}

and

Beleg: Elf of Doriath, a great archer; friend and companion of Túrin. Called Cúthalion ‘Strongbow’.

That said, there's no specific reason to assume he was the single greatest elf archer.

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Orc

The orcs are invariably described as a bit crap with a bow, relying on mere force of numbers and volume of (poisoned) arrows to do damage:

Behind them orc-archers crowded, sending a hail of darts against the bowmen on the walls. - _{^{LotR: TTT}}

and

Dismayed the rammers let fall the trees and turned to fight; but the wall of their shields was broken as by a lightning-stroke, and they were swept away, hewn down, or cast over the Rock into the stony stream below. The orc-archers shot wildly and then fled. _{^{LotR: TTT}}

and

But orc-arrows are plenty, and the sight of one would not be taken as a sign of Doom by Boromir of Gondor. _{^{LotR: TTT}}

and

The orcs hindered by the mires that lay before the hills halted and poured their arrows into the defending ranks. - _{^{LotR: RotK}}