Anderson, who turns 43 this month, returned to T20 cricket this year
after an 11-year absence and has taken 14 wickets in eight appearances for Lancashire in the Vitality Blast, operating as a new-ball specialist. He initially went
unselected in March's Hundred draft but will now play for the Originals in August after he was picked up in Tuesday's 'wildcard' draft on a £31,000 deal.
Flintoff's selection will raise eyebrows given he is yet to play in the Blast and his father is Superchargers head coach. But he has already shown his obvious promise with a century for England Lions in Australia this winter and a recent hundred for England's Under-19s against India.
Elsewhere, Southern Brave became the first team to sign an overseas player as a wildcard - Australia's
Hilton Cartwright - after replacing Faf du Plessis with Jason
Roy last week. They have also picked up the young Hampshire batter
Toby Albert, who could keep wicket for them amid injury concerns around Finn Allen and Laurie Evans.
Ben Kellaway, the Glamorgan allrounder and ambidextrous spinner, has signed for Welsh Fire after a breakout season at county level, while
Ben Sanderson, who has enjoyed his best-ever T20 season for Northamptonshire this year, will play for Trent Rockets.
In the women's wildcard draft,
Esmae MacGregor earned a deal with Manchester Originals after taking 21 Blast wickets for Essex, while Hampshire's
Mary Taylor joins her twin sister Millie at Birmingham Phoenix.
The Hundred runs from August 5-31, opening with London Spirit's double-header against Oval Invincibles at Lord's.
Men's Hundred wildcards (all £31,000):
Trent Rockets: Callum Parkinson, Ben Sanderson
Birmingham Phoenix: Liam Patterson-White, Louis Kimber
Welsh Fire: Ajeet Singh Dale, Ben Kellaway
Northern Superchargers: James Fuller, Rocky Flintoff
Manchester Originals: James Anderson, Marchant de Lange
London Spirit: Sean Dickson, Ryan Higgins
Oval Invincibles: George Scrimshaw, Zafar Gohar
Southern Brave: Toby Albert, Hilton Cartwright
Women's Hundred wildcards (all £10,000):
Birmingham Phoenix: Mary Taylor, Phoebe Brett
London Spirit: Abi Norgrove, Kate Coppack
Manchester Originals: Esmae MacGregor, Darcey Carter
Northern Superchargers: Katherine Fraser, Sophia Turner
Oval Invincibles: Daisy Gibb, Rebecca Odgers
Southern Brave: Phoebe Turner, Amara Carr
Trent Rockets: Grace Thompson, Sophie Morris
Welsh Fire: Charley Phillips, Alex Griffiths.