The "Elites". Who are they exactly?

Concentrated power exists, but it's not monolithic. Billionaires compete with each other. Political dynasties rise and fall. Different industries lobby for conflicting interests. What looks like coordinated control is usually just shared incentives, social homogeneity among the wealthy, and institutional inertia.
The "elites" aren't a single committee. They're a loose network of people with money, institutional position, and cultural influence who often but not always move in the same direction because they share similar backgrounds, education, and economic interests.

The "Elites" are whoever the far-right doesn't like.

The terms "Deep State" and "Globalists" originally referred to the rich donors who basically controlled the government through their wealth. That's how I use those terms. So those would be the "Elites" too. It's not a conspiracy, it's just Capitalism.

The Trumps. A man who feathers his own nest at the expense of his followers, and they love him for it.

They are whoever the critic decides at the time....

Nevertheless there are too many very wealthy, shallow-minded and very greedy people mixing money and politics; intending the money being their own, ultimately, whatever its source. (Taxpayers, business customers, shares-buyers)

Good question. Most of the time I think it’s just a short hand way of saying ‘things I have no control over and someone must be blamed’.

I've sometimes replied to posts that accuse "the elites", "the deep state" and the like of some ill-defined wrong-doing, by asking just who these people are.

My question was not answered, suggesting to me the writer did not really know but just likes repeating cliches to cover not really understanding the matter.

They are the ones in control. Their alliances are only towards themselves. They throw a red herring in the tank every now and then to get us fighting one another. That way we can't see them.