An important early 20th-century abstract algebra textbook that was superseded by van der Waerden is:

Haupt, O., 1929, Einführung In Die Algebra, Zweiter Band - Mit Einem Anhang Von W. Krull, Akademische Verlagsgesellschaft M. B. H., Leipzig.

Two important early 20th-century abstract algebra textbooks that were superseded by van der Waerden are:

Hasse, H., 1926. Höhre Algebra.

Haupt, O., 1929, Einführung In Die Algebra, Zweiter Band - Mit Einem Anhang Von W. Krull, Akademische Verlagsgesellschaft M. B. H., Leipzig.

For an in-depth historical account of the transition from algebra to abstract algebra (including discussions of the various textbooks) see:

Leo Corry, 1996, Modern Algebra and the Rise of Mathematical Structures, Birkhäuser Verlag.