A modern introductory book to differential equations is Fundamentals of Differential Equations and Boundary Value Problems (6th Edition, 2011) [Hardcover]
R. Kent Nagle, Edward B. Saff, Arthur David Snider
https://www.amazon.com/dp/0321747747/?tag=pfamazon01-20
I have the 4th edition from 2004.
Perhaps more commonly used books are those of Boyce and DiPrima (back when I was at university ~30+ years ago). I have the 3rd Ed of Boyce and DiPrima from 1977.
Elementary Differential Equations and Boundary Value Problems [Hardcover]
William E. Boyce and Richard C. DiPrima
https://www.amazon.com/gp/product/0470458313/?tag=pfamazon01-20
Elementary Differential Equations [Hardcover]
William E. Boyce, Richard C. DiPrima
https://www.amazon.com/dp/047003940X/?tag=pfamazon01-20
Perhaps my favorite is one by George F. Simmons, Differential Equations with Applications and Historical Notes, McGraw-Hill. My copy is from 1972, but there are more recent editions by the same author.
Differential Equations: Theory, Technique, and Practice (Walter Rudin Student Series in Advanced Mathematics) [Hardcover], 2006
George Simmons, Steven Krantz
https://www.amazon.com/dp/0072863153/?tag=pfamazon01-20