The phrase "a cast of highly" is correct and usable in written English.
It can be used when describing a group of individuals, often in the context of performers or experts in a particular field.
Example: "The film features a cast of highly talented actors who bring the story to life."
Alternatives: "a group of highly" or "a team of highly".
And thanks to Rob Berman and the Encores! orchestra, a cast of highly competent singers, and the scene-summoning efficiency of the director Gary Griffin and the choreographer Alex Sanchez, those melodies can be savored firsthand (or first-ear) in all their lively variety.
With the Hereafter Institute, Barcia-Colombo enlisted a cast of highly convincing white-cloaked "consultants" to walk museumgoers, a.k.a., "clients," through various memorialization options and foster a dialog about what happens to one's online presence after death.
The novel features "a sprawling cast of highly cinematic characters, an air of pungent menace, a full-to-bursting package held together by a strong, suspenseful plot," Mark Costello wrote in the Book Review in 2003.
The story of Saartjie Baartman — the Hottentot Venus's real name — is inherently fascinating, and littered with a diverse cast of highly unlikable characters, ranging from Baartman's lowly black South African master, Hendrik Cesars, to the foremost European scientist of the day, Georges Léopold Chrétien Cuvier.
The way the Russians did it was to have this cast of highly respected criminals who [are] able to be a judge.
It is itself highly engaging, with a cast of characters that includes Andy Warhol, Norman Mailer, Nadine Gordimer, William F. Buckley and Annie Leibovitz.
Journalism is starting to look like sports, where a cast of role players serves as a platform and context for highly paid, high-impact players.
There were a cast of characters.
This took a cast of his body.
