Do most regular English plurals end with -s or -es?

This could lead to a more complicated answer than you're looking for. The most common English plural ending is just -s.

Ex.

piece -> pieces

pie -> pies

dog -> dogs

house -> houses

ant -> ants

axe -> axes

key -> heys

However, -es is used when pluralizing singular nouns that end in -s, -z, -sh, x, or -ch.

Ex.

mess -> messes

mantis -> mantises

hex -> hexes

buzz -> buzzes

bush -> bushes

lunch -> lunches

But watch out! If is ends in -us, the -us is replaced with -i to make it plural.

Ex.

radius -> radii

octopus -> octopi

Another alternate ending is -ves, used to pluralize singular nouns that end in -f or -fe. The "v" replaces the "f".

Ex.

leaf -> leaves

knife -> knives

handkerchief -> handkerchieves

In addition, nouns that describe things collectively require a Word like "piece" if you want to indicate there is exactly one part of it. Otherwise, it always sounds plural.

Ex.

hair -> strand of hair

grass (of one species) -> blade of grass

meat -> piece of meat

fish -> a fish

Then, of course, there are exceptions to every rule