There are many DevNet Sandbox labs that can aid help you achieve your CCNA certification. It all depends on what certification you want. In the last number of months, the CCNA course has changed somewhat. It is now split onto the following:
CCNA Routing and switching
CCNA Service Provider
All of the information you need is on this page:
I am not familiar with the content of all of these courses. If you goto the sandbox home page you will see categories listed on the right. Browse through the labs (and lab instructions) to see if it meets your needs. Just some thoughts of my own:
APIC EM Hardware Mini labs: Direct access to play with Cisco routers and switches. There is also an APIC controller i here to integrate northbound APIs. This would be useful for the Routing and Switching exam.
Sandbox Collaboration Labs: Our collaboration labs contain a wealth of Cisco collab servers including Unified Communications manager, Unified Presence, Voicemail, Jabber Guest and Client, mediasense etc. Private access to these environments would be very useful for CCNA Collaboration
ACI Simulator and Open NX OS: CCNA Datacenter
Firepower and PXgrid: CCNA Security
Our Sandbox labs are not directly connected to any CCNA course. However, I am sure you will find lab(s) useful to you during your study.
DevNet also runs Learning Lab modules for a large number of technologies. These labs bring you through a specific API in detail. I would recommend you take a look at these as well.
Please let us know how you get on and feel free to suggest improvements to our service.