There are many applications and tools DevOps engineers use on a daily basis. But without some of the essential apps it would be hard to develop and rollout automation tools and processes. Any attempt at kickstarting DevOps culture should include plans to make those apps available as core infrastructure to the team.
What if such an exercise would begin with a list of solid, battle-tested open-source tools which won’t cost you a dime in license fees. You might end up with a set of tools that would fit your budget and comfort level at the end, but, make such decisions only after closely looking at the tools listed here. Please see the complete list in a recent article I contributed to DevOps.com.
I am open to suggestions and changes in the list if you would make a good case for your favorite tool. I agree upfront that the selection of these tools is heavily influenced by my hands-on experience successfully using those in various DevOps projects.