The phrase "a catalog of about" is correct and usable in written English.
It can be used when referring to a collection or list of items, typically indicating an approximate number or range.
Example: "The library has a catalog of about 500 books on modern art."
Alternatives: "a collection of approximately" or "a list of around".
By buying small publishers, it has quickly built a catalog of about 300,000 songs.
Ascap represents more than 170,000 songwriters, lyricists and music publishers and has a catalog of about eight million musical works.
When Mr. Dalton arrived at C.R.I. in 1990, the label had a distinguished history and a catalog of about 400 discs.
The Almagest includes trigonometric tables and a catalog of about 1,000 stars, which was probably based substantially on an earlier catalog by Hipparchus but with additions and modifications by Ptolemy.
Temminck's earliest publication was a catalog of about 1,100 species in his father's large collection, called Catalogue systematique du cabinet d'ornithologie et de la collection de quadrumanes de Crd.
So far, that's attracted a catalog of about 2,000 titles that can be viewed on demand.
The slow travel meant that explorers and pilgrims frequently returned with a catalog of stories about far-off lands: some of them wild tales, some honest renderings.
Project Navigator offers users a catalog of information about the various OpenStack projects, including data about their maturity and packaging, as well as documentation support.
When the Icelandic director Gisli Orn Gardarsson needed music for his production of "Woyzeck," the 1837 play about an ordinary man pushed past his limits, he went to Nick Cave, known for a catalog of songs about murder, obsession and bad, bad love.
The guitar-slinging songwriter Bill Morrissey has a well-weathered voice and a catalog of songs about characters who have seen their share of troubles.
Focus groups conducted for a panel of scientists advising the government uncovered a catalog of misinformation about the smallpox vaccine -- the first vaccine to be developed (in 1796) and considered to be the most dangerous.
