The following list of resources was very useful to me when I was studying for the Cisco DevNet Associate exam. You may need either a free Cisco account or a free Cisco University account to access some of the links below.

Resource Description
Study Plan Core DevNet Associate study materials.
Learning Map Additional learning exercises.
Preparation Program A preparation program which works through some of the core topics that are covered in the exam.
Network Automation Essentials Online Cisco University course that works through the Network Automation Essentials topics that are required for the DevNet Associate exam.
Learning Dashboard Displays your active learning tracks.
DEVNET Sandbox A free sandbox environment where you can test your developed software on virtual Cisco equipment.
Additional Learning Tracks Further your understanding through these additional learning tracks.
Main Developer Site Contains additional links to sample code, learning labs and documentation.
YouTube Link to the official Cisco DevNet YouTube channel.
Practice Quiz Practice quiz that contains questions that will help to prepare you for the exam.
Software Defined Networking Link to materials on the concept of software defined networking which is a core topic in the DevNet Associate exam.
PluralSight Link to a PluralSight course which goes through the core material of the DevNet Associate course. Note: Subscription required to access the video.