Learn English – single word for “one who explains his point of view very clearly”

Some possible ideas for you:

A go-to player:

She's the team's go-to player [=she is the player that the team relies on] when they need to score late in the game.

You can also simply state that X is a most important player (MIP) or most valuable player (MVP) for the team.

The teams that rely heavily on one man to win a match are called one-man teams:

With Neymar gone, suddenly Brazil’s ‘one-man team’ lacks a man. (source)

Use abundant (overabundant) to describe something that exists in large amounts that are more than what's needed.

Near synonyms are plentiful, emphasizing "large amounts," and ample, emphasizing "more than enough

"Our oceans provide sustenance galore."

galore

Galore means there’s so much that it’s unbelievable. The word is an example of a postpositive adjective, which means it comes after the word it describes. (vocabulary.com)