For the Trump aides, one potential drawback is that they will now take government salaries, which for many will amount to a cut in pay as they refrain from outside work to avoid conflicts. When their time in the administration ends, however, they could find even more riches waiting for them.

The arrangement has been especially lucrative for insiders and key operatives with links to the biggest donors, and those closest to Mr. Trump, despite his campaigning on an anti-establishment message and his disparagement of business as usual in Washington.

The White House did not respond to a request for comment from the aides included in this article.

The list of income sources for those in Mr. Trump’s White House reads like an encyclopedia of conservative wealth and influence. Many of Mr. Trump’s aides have earned money from right-leaning media organizations like Breitbart and Fox News, or from a firm set up by Newt Gingrich, the former House speaker, to manage his speaking and television appearances. Several aides received payments from organizations backed by major conservative benefactors such as the Kochs or the Mercers. Others were paid for work on Republican campaigns, including Mr. Trump’s or that of Senator Ted Cruz of Texas, a onetime rival.

Few Trump advisers are as plugged into the old and new worlds of political money as Kellyanne Conway, counselor to Mr. Trump. As a Republican strategist and pollster who ran a consulting firm, Ms. Conway earned more than $800,000 from her firm and reported 75 sources of income.

Among the clients that paid her at least $5,000 were the Tea Party Patriots, a group founded in 2009 to oppose Mr. Obama’s health care and spending initiatives, and the Judicial Crisis Network, a nonprofit group that has spent millions of dollars, raised from wealthy donors, in an effort to reshape the federal court system.

She advised nearly a dozen candidates on their campaigns, including Mr. Trump and Mike Pence, now the vice president. Ms. Conway also earned money from speaking appearances at conservative think tanks like the Alabama Policy Institute and the John Locke Foundation.