The phrase "a substantial collection" is correct and usable in written English.
It can be used to describe a large or significant group of items, often in contexts such as art, literature, or data.
Example: "The museum boasts a substantial collection of ancient artifacts that attract visitors from around the world."
Alternatives: "a significant collection" or "a considerable collection".
The hall has a substantial collection of artefacts collected over the years.
A substantial collection of 228 papers was collected at UCL Institute for Sustainable Heritage from different sources in Central Asia, Near East and North Africa (15th 19th century) for the purpose of material analysis (ref-collection).
Ms. White and Mr. Levy amassed a substantial collection of classical art over several decades.
The Berenson Library also holds a substantial collection of manuscripts and early printed material on microforms.
A substantial collection of ornithological reference works, bibliographies, and histories provides full support for the Hill Ornithological Collection.
They donated it to the Rosenbach Museum and Library in Philadelphia, which holds a substantial collection of Sendak materials.
A more substantial collection, Descartes and the Animals, followed in 1954.
Ultimate Jordan is a much more substantial collection of four highlight films from Jordan's career as well as five key games from his career in their entirety along with other extras.
He was seeking a repository for his substantial collection of disco memorabilia (including an opening-night invitation to Studio 54) and records.
Serena Williams will ring in the new year by adding an engagement ring to her substantial collection of tennis trophies.
Finally, Special Collections at the Speer Library of the Princeton Theological Seminary, an independent educational institution located in Princeton, has a substantial cuneiform collection, with some three thousand items.
