Complex sentence: In 1926, she gifted her already significant collection of over 100,000 trade cards to the New York Historical Society, where she was made an unpaid honorary curator to which she continued to collect, catalog and conduct research on the collection.
Split into simpler sentences: In 1926, she gifted her already significant collection of over 100,000 trade cards to the New York Historical Society. She was made an unpaid honorary curator, and she continued to collect, catalog and conduct research on the collection.