The phrase "actually a collection of" is correct and usable in written English.
It can be used to clarify that something is not just a single item but rather a group or assortment of items or elements.
Example: "The exhibit is actually a collection of rare artifacts from ancient civilizations."
Alternatives: "essentially a group of" or "fundamentally a set of".
The fig itself is actually a collection of many of these achenes surrounded by the fleshy tissue of the syconium.
The meeting was meant, in part, to celebrate the conclusion of a $3 billion campaign, actually a collection of individual campus efforts.
But the building itself — actually a collection of three connected brownstones — has become a problem, said Dr. Scelsa, who has a Ph.D. in education.
It is actually a collection of artists who mostly do other things and who just happened to make an artwork or two related to sweets.
Where Not quite as expensive as neighbouring Courchevel, this chalet-style resort is actually a collection of hamlets spread around the mountainside.
This 40-year-old so-called resort is actually a collection of tiny bamboo eating places spread out along 500 yards of riverbank.
A lens actually contains a collection of several lenses.
"But," he adds, sounding more prolific by the second, "I think I will actually finish a collection of stories before I finish the novel".
As is the case now, the new forecasts will actually be a collection of forecasts from the presidents of the Fed's 12 regional banks and from the central bank's governors, who sit on the Federal Reserve Board.
We have to actually create a collection of physical prototypes and appearance models to make sure it feels comfortable, and has the right size.
The difficulties posed by the discontinuous nature of the loss of performance function, which actually comprises a collection of distinct curves, are dealt with by aggregating them into a continuous surface obtained via best fitting methods.
