The bookies have the Portuguese giants at 3/1, with Chelsea just behind at 4/1 to be Ronaldo's club by the end of the January transfer window.
Any MLS club is third favourite at 6/1, with Newcastle lurking just behind at 15/2. A surprise return to Real Madrid is at 8/1 and any Saudi club is at (10/1).
The European giants of Bayern Munich (10/1), Napoli (12/1), AC Milan (16/1), Roma (16/1) and PSG (18/1) are also in the queue. Even Arsenal have snuck in at 16/1.
Planet Sport looks at Ronaldo's options.
Sporting Lisbon (3/1)
Ronaldo became a global star during his first period with United but it was Sporting that helped cultivate his early talent.
The forward has regularly been linked with a return to the club he left aged 18 and retains a strong connection with the Primeira Liga side, who have a section dedicated to him in their museum and renamed their academy training facilities after him.
The player's mother, Dolores Aveiro, has previously said she wants to eventually see him back playing for the Lisbon club.
While it never got beyond initial conversations over the summer, Chelsea sounded Ronaldo out about a potential switch that the Portugal ace was reportedly open to.
Former Blues boss Thomas Tuchel was not thought to be keen on the switch but he is long gone and with successor Graham Potter suffering a rocky start at Stamford Bridge, the idea could once again appeal to Todd Boehly's ownership group.
Money should not be a major stumbling block and if the opportunity arose, the chance to end his Premier League journey on a high could be irresistible.
Major League Soccer (6/1)
A number of European football's biggest names have taken up the option of seeing out their days in the United States, with the likes Frank Lampard, Steven Gerrard and Wayne Rooney among their number.
Ronaldo's A-list status would make him the kind of draw that could pull serious commercial interest in MLS and the lifestyle across the Atlantic would hardly put off a player who long ago became a crossover celebrity.
LAFC, Los Angeles Galaxy and Beckham's Inter Miami have all been touted as potential suitors.
Newcastle certainly have deep pockets, but so far the club have avoided bringing in a megastar the Toon army have been craving for.
Eddie Howe has brought together a group of players who have a real teamwork ethic and surely the Ronaldo spotlight goes against everything the manager is trying to bring to the club.
Would Ronaldo want to move to the North East anyway?
Saudi Arabia (10/1)
When Ronaldo last appeared to be on the way out of Old Trafford over the summer, none of Europe's elite swooped for the star.
A swathe of names were mentioned as potential destinations but the only offer came from Saudi Arabia.
It is reported that Al Hilal were the club who approached Ronaldo about a potential two-year deal worth 275million euros (£233.4million). That was not attractive enough then but perhaps things are different now.
Dropping into the Europa League may not be Ronaldo's first preference and Roma's current league position of seventh means a league trophy looks a long shot.
But the presence of compatriot Jose Mourinho in the dugout could be intriguing. The pair enjoyed great success together at Real Madrid, harbour similar frustrations about their treatment by United and may decide to put their star power together in one last roll of the dice.