Former president Barack Obama speaks in Helsinki on Sept. 27, 2018. (Jussi Nukari/AP)

Former president Barack Obama announced his second wave of 2018 endorsements Monday, unveiling a list of candidates in 29 states that includes several big-name Senate and gubernatorial hopefuls — as well as some noticeable absences, including Texas Senate nominee Beto O’Rourke.

The move comes a little over a month before Election Day and as Democrats are optimistic about their chances of riding a blue wave to retake the House and possibly the Senate.

“Today, I’m proud to endorse even more Democratic candidates who aren’t just running against something, but for something — to expand opportunity for all of us and to restore dignity, honor, and compassion to public service,” Obama said in a tweet announcing the list.

Among the notable names on the list are more than a dozen gubernatorial nominees who reflect Democrats’ broader embrace of ethnically diverse, female and LGBT candidates in this year’s midterms. They include Andrew Gillum in Florida, Ben Jealous in Maryland, Gretchen Whitmer in Michigan, Michelle Lujan Grisham in New Mexico and Christine Hallquist in Vermont.

If elected, Gillum and Jealous would become the first black governors of their states. Hallquist is the first openly transgender person to win a major party’s gubernatorial nomination.

Four Senate nominees also made the list: Kyrsten Sinema in Arizona, Bill Nelson in Florida, Tina Smith in Minnesota and Tammy Baldwin in Wisconsin. Nelson, Smith and Baldwin are incumbents, while Sinema is a House member.

Several insurgent House candidates received the nod from Obama. They include Alexandria Ocasio-Cortez, the 28-year-old activist and democratic socialist who defeated 10-term Rep. Joseph Crowley (D-N.Y.) in June, and Ayanna Pressley, who ousted veteran Rep. Michael E. Capuano (D-Mass.) last month and is on track to become the first black woman to represent her state in Congress.

Nancy Soderberg, a former Clinton national security aide who also served as chair of Obama’s Public Interest Declassification Board, was on the list, as well. Soderberg is vying for the House seat of Rep. Ron DeSantis (R-Fla.), who is running for governor.

One noteworthy omission from the list was O’Rourke, the three-term congressman who is aiming to unseat Sen. Ted Cruz (R-Tex.) in one of the most closely watched races in the country. The liberal, 45-year-old O’Rourke has drawn crowds of thousands to his events — a rally Saturday night with country music legend Willie Nelson drew a reported 55,000 people — prompting no shortage of comparisons to the rock star aura that surrounded Obama during his campaign days.

Other well-known Democrats, such as New York Gov. Andrew M. Cuomo and Sen. Robert Menendez (N.J.), were absent from the list, as well.

As he did in his first round of endorsements in August, Obama also backed a host of candidates for state legislature.

Obama’s office has previously said that the former president is making it a priority to support candidates backed by the National Democratic Redistricting Committee, led by former U.S. attorney general Eric H. Holder Jr., with the aim of giving Democrats a greater voice in the process of drawing legislative district lines.