
Groups seeking a speaker on diversity and immigration can call on Rosario Dawson. Though she’s best-known as an actress—in a number of films as well as on Broadway—Dawson also is an activist. She is a co-founder of Voto Latino, which encourages civic engagement among young Latinos, and a fashion line called Studio 189—a platform to promote and curate African content. Her agency, CAA, provides pricing upon request.

Having served as White House director of economic policy under George H.W. Bush, managing director of the $15 billion Tiger hedge fund, and a Harvard professor, economist Todd Buchholz delivers talks on economics, fiscal politics, finance, and business strategy. Represented by Goodman Speakers Bureau, his range of speeches include one entitled, “The Hope and Danger Behind World Politics.” His fee is $10,000 to $20,000.

Former CNBC chief economist and Federal Reserve and Oppenheimer Funds economist Marci Rossell has spoken not just to finance-related groups but also to engineering organizations, agribusiness audiences, and others. She covers regulation, how the politically charged Federal Reserve operates, how changes such as the mid-term elections could change funding on projects, and more. Represented by Promenade Speakers Bureau, Rossell charges $20,000.

Oscar-winning screenwriter and filmmaker Dustin Lance Black works to raise awareness of violence and discrimination committed against L.G.B.T. people around the world. The recipient of the Academy Award for Best Original Screenplay for Milk is a founding board member of the American Foundation for Equal Rights, and has blended creative and civil rights efforts with 8, a play based on the federal trial challenging California's Proposition 8 that restricted the right of same-sex couples to marry. A frequent guest on MSNBC and CNN, he often is named as one of the most powerful members of the L.G.B.T. community. His agency, CAA, provides pricing upon request.

As the inaugural chair of information integration at the Department of Defense, as well as the founder of the Strategic Narrative Institute, “global futurist” Amy Zalman is an expert on worldwide trends who can speak about cyber security, approaches for managing change, grasping the impact of emerging trends, and branding or storytelling. The former C.E.O. and president of the World Future Society, which serves as an advocate on future-critical issues, is represented by Promenade and charges $7,500 to $10,000.

Tax attorney Andy Friedman, who has served as the tax advisor to Major League Baseball and several other sports organizations, is known for his talks on political and legislative developments, as well as his ability to accurately predict the outcomes of Washington’s battles. He provides audiences with investment strategies to consider, given the political landscape, pulling from nearly 30 years of experience at the law firm of Covington & Burling. Represented by Goodman, Friedman charges a $10,000 to $20,000 speaker fee.

The YouTube personality Jenna Marbles (whose real name is Jenna N. Mourey) reaches more than 15.4 million subscribers and is the most popular woman on the social media site. Fresh off an appearance last week on James Corden’s The Late Late Show, Marbles posts a variety of videos, from ones starring her dog to an impersonation of Hillary Clinton. As a speaker, she can discuss her journey and the challenges she’s overcome to achieve YouTube stardom while authentically connecting with fans. She is represented by CAA Speakers.

The Vine and Snapchat specialist Jerome Jarre is a favorite of brands like Pepsi and has been profiled by Fast Company, People, and The New Yorker, among others. His Vine following grew to 8.5 million, making him one of the top users on the service. His native French accent and huge smile feature prominently in the 25-year-old’s posts and endear him to fans. With social media guru Gary Vaynerchuk, Jarre co-founded the mobile marketing agency Grape Story, and he can share his tips for using mobile marketing to reach customers through engaging and interactive stories. He is represented by CAA Speakers.

Filmmaker Sawyer Hartman uploaded his first short film to YouTube in 2011 and since then has amassed a following of more than 1.8 million subscribers. His latest project, a full-length feature called The Parallax Theory, debuts on Vimeo on September 22. He is represented by the Gersh Agency.

The comic video specialist Timothy DeLaGhetto, also known as Traphik, counts more than 2.9 million subscribers and 601 million views of his posts, which show off his skills as a rapper, comedian, writer, and videographer. His work includes original skits, parodies, rants, and a series called “Dear DeLaGhetto.” He currently appears as a cast member on MTV’s Wild N’ Out and Guy Code. DeLaGhetto, who is Thai-American, can speak to groups about his creative process and how diversity plays a role in content, audience reach, and success. He is represented by CAA Speakers.

A classically trained violinist who now pairs her music with electronic beats, Lindsey Stirling used YouTube to promote her early career and now has more than 6.9 million followers. Stirling calls her rejection in the quarterfinals of the TV show America’s Got Talent in 2010 a defining moment, and she has gone on to success that included a nomination at this year’s Teen Choice Awards for Choice Web Star: Music. Raised as a Mormon, Stirling can speak about inspirational topics such as her faith, not giving up, remaining strong and true to yourself, overcoming trials, personal progress and change, her prior struggle with an eating disorder, and positive thinking. She is represented by WME.

YouTube pioneer Philip DeFranco—he joined in 2006—produces a humorous news and pop culture show Monday through Thursday that reaches nearly 3.5 million subscribers. At events, DeFranco can perform a live version of “The Philip DeFranco Show.” He is represented by CAA Speakers.

Yousef Saleh Erakat, better known as FouseyTube, has a combined following of more than 6.7 million subscribers on his four YouTube channels. His videos, which include pranks, social experiments, and comedy sketches, nearly always have a moral undertone, which he can translate to speaking appearances. He is represented by CAA Speakers.