"invaluable partner" is correct and can be used in written English.
You can use it to describe someone who has been a significant help or contributor to a project or venture. For example, "My coworker has been an invaluable partner in helping me to develop this project."
Blair claimed post-2004 Libya had become an invaluable partner in countering terrorist violence.
A welleducated woman of great intelligence and insight she was her husband's invaluable partner in building his outstanding legal career.
The WELL for Life team has been an invaluable partner". Get in touch and become a community partner today!
Evelyn Lauder was a source of inspiration and hope to those battling breast cancer and an invaluable partner to scientists in the quest for a cure.
Both China and the Soviet Union have come to see Japan as an invaluable partner in their drive for economic development and for security against each other.
As the year pressed on, Jacobs had an invaluable partner and increasingly close friend in Julia Ann Wilbur, a Quaker from upstate New York, who had laid the groundwork for receiving refugees in Alexandria beginning in 1862.
They are dedicated teachers and mentors to undergraduates and invaluable partners to faculty in creating new knowledge.
All of them quickly grew into invaluable partners and functional mentors once they did join though.
We also would like to give a special shout out to 10up developers, John Bloch, Eric Mann and Luke Gedeon, who were invaluable partners with us on the project.
In adding our voices and actions to the greater national discourse, HACR, NALEO, NCLR, USHCC and Miami Dade College, have been invaluable partners along with dozens of organizations that are convening at the First Biennial American Latino Summit in Miami this September 24.
"The people you see around me are invaluable partners," added Chaiban, as he turned to the assembled representatives.
