The 14-strong roster is headed by Triple Crown winners Justify and American Pharoah, both currently serving mares at Coolmore Australia.
Justify will stand for an advertised fee of $US150,000, unchanged from his debut season in 2019.
The fee for American Pharoah will be announced after the Breeders' Cup next weekend where he is expected to be represented by two runners.
Ashford's other six-figure sire on the roster is Uncle Mo, who will stand for an unchanged fee of $US125,000.
WinStar Farm has set 2020 stud fees for its 21-stallion roster, headed by veteran shuttle sire More Than Ready who will stand for an unchanged fee of $US80,000.
Speightstown ($US70,000) and Tiznoiw ($US40,000) are also on the roster.
WinStar also welcomes new stallions in G1 Florida Derby winner Audible who will stand his initial season at stud for $25,000 and G1 Breeders' Cup Classic contender Yoshida, whose fee is to be determined.
The roster also includes leading first crop sire Constitution, whose fee has moved to $US40,000, Kentucky Derby winner Always Dreaming ($US25,000) and the leading third crop sire Take Charge Indy ($US17,500).
This year's 2000 Guineas winner Magna Grecia has been retired from racing and will stand at Coolmore Stud in Ireland in 2020.
A 340,000gns yearling, Magna Grecia won the G1 Futurity Trophy as a 2YO and as a first-up winner of the 2000 Guineas at Newmarket in May, making him the only son of Invincible Spirit to win G1 races in his first two seasons.
Coolmore's David O'Loughlin said, "Magna Grecia is a top class prospect by the sire of Kingman. He's got the pedigree and the good looks and he beat so many good horses in both the Futurity and the 2000 Guineas."
The Irish National Stud will stand Phoenix Of Spain, the winner of this year's G1 Irish 2000 Guineas, in 2020.
Trained by Charlie Hills for Tony Wechsler and Ann Plummer, Phoenix Of Spain won twice as a 2YO including the G3 Acomb Stakes and second to Too Darn Hot in the G2 Champagne Stakes and to Magna Grecia in the G1 Futurity Trophy.
The son of Lope De Vega won the Irish 2000 Guineas first-up as a 3YO, beating both To Darn Hot and Magna Grecia.
Taj Mahal, the Galileo import who won the G2 Zipping Classic at Sandown in 2017 and 2018 for Lloyd Williams, will go to stud in France in 2020.
Taj Mahal (Galileo x You'resothrilling by Storm Cat) has been retired to stand at Haras de la Haie Neuve in Brittany.
His dam You'resothrilling was a juvenile G2 winner and is a full sister to European Horse of the Year and top sire Giant's Causeway and has produced five stakes winners from six foals to race including Taj Mahal, four-time G1 winner Gleneagles (Galileo), champion filly dual G1 winner Happily (Galileo), G1 Irish One Thousand Guineas winner Marvellous (Galileo) and G3 winner Coolmore (Galileo).
Classic winner and successful sire Rebel Raider died last week at Victoria's Wyndholm Park Stud after suffering a ruptured aorta.
The son of Reset won six races including the G1 Victoria Derby and the G1 South Australian Derby.
His has sired more than 130 individual winners including the G3 winners Pretty Punk and Waging War and G1 placed pair Rockstar Rebel and Miner's Miss.