Dumas himself had a personal library of about 6,000 books at its peak. If you don't already have them on your list, historians have mentioned several books that were known to have strongly influenced him:
Walter Scott's historical novels, particularly "Ivanhoe" and "Waverley," which inspired Dumas' approach to historical fiction
James Fenimore Cooper's frontier adventures, which influenced his action narratives
Lord Byron's romantic poetry and persona, which shaped Dumas' conception of the romantic hero
Schiller's play "The Conspiracy of Fiesco at Genoa," which Dumas translated and adapted early in his career
Shakespeare's dramatic works
Memoirs of historical figures, particularly those from the 17th and 18th centuries, including Courtilz de Sandras' "Mémoires de M. d'Artagnan," which became the foundation for "The Three Musketeers"
Plutarch's "Lives," which informed his understanding of classical historical figures
Works by Abbé Prévost and other French novelists of the 18th century
Walter Scott's historical novels, particularly "Ivanhoe" and "Waverley," which inspired Dumas' approach to historical fiction
James Fenimore Cooper's frontier adventures, which influenced his action narratives
Lord Byron's romantic poetry and persona, which shaped Dumas' conception of the romantic hero
Schiller's play "The Conspiracy of Fiesco at Genoa," which Dumas translated and adapted early in his career
Shakespeare's dramatic works
Memoirs of historical figures, particularly those from the 17th and 18th centuries, including Courtilz de Sandras' "Mémoires de M. d'Artagnan," which became the foundation for "The Three Musketeers"
Plutarch's "Lives," which informed his understanding of classical historical figures
Works by Abbé Prévost and other French novelists of the 18th century
The Bible and classical mythology