The full list, which included the junta leader's brother and scores of military officers, was appointed by junta number two Prawit Wongsuwan, endorsed by King Maha Vajiralongkorn and published in palace mouthpiece The Royal Gazette.
Army Chief Apirat Kongsompong and National Police Chief Jakthip Chaijinda are now senators, as expected, thanks to a controversial military-scripted constitution adopted in 2017.
But Prawit also selected some 100 serving and retiring military and police officers -- making up 40 percent of the senate. He also picked more than 50 members of the rubber-stamp National Legislative Assembly (NLA), and 15 ministers to be elevated to the senate.
Well-known family names of the junta's top-ranking officials and allies are on the list as well, most notably Prayut's younger brother Preecha Chan-O-Cha, who retired from his position at the NLA last week.
Joining him are siblings of Prawit and deputy prime minister Wissanu Krea-ngam, as well as the older brother of deputy prime minister Somkid Jatusripitak.
The younger brother of army-aligned fortuneteller Warin Buawiratlert -- who predicted coup leader Prayut would hold onto power after the March 24 poll -- will also be in the senate.
The 250 members will vote alongside 500 elected lower house MPs to select the prime minister after parliament convenes in the coming weeks.
With the senate in hand, junta-backed Palang Pracharat will need only 126 votes in the lower house for Prayut to sail to the top position.
Anti-junta parties would require a whopping 376 votes to gain a majority in the 750-seat parliament and override the senate advantage.
So far, the coalition led by junta rival Pheu Thai, linked to billionaire ex-premier Thaksin Shinawatra, holds 245 seats against the 135 promised to Palang Pracharat.
Horsetrading and negotiations for the remaining seats are under way.
"The nepotism is blatant" in the senate appointments, said analyst Paul Chambers of Naresuan University, adding that the endorsement sends a "negative message" to parties trying to scoop up more seats.
"Palang Pracharat now has the upper hand."