The title is “The New Webster’s Library of Practical Information: Quotations”. ISBN: 0-7172-4565-9, and the only link I found that was representative of what the set I have resembles is below[0], though it’s worth noting that it’s quite overpriced in said link (afaik) so please don’t take this as a purchase recommendation.

Apparently newer additions have been released as individual books (not as part of a set), and I’m sure you could snag a free pdf of a dictionary of quotations via libgen for a quick peek.

[0] https://m.ebay.com/itm/The-New-Websters-Library-of-Practical...