Appreciating this lays out the boundaries for the the more borderline stuff. An example of this, IMO, is things like unit testing and mocking frameworks. Most are pretty similar, and offer similar functionality, but perhaps with slight differences in capability or approach to solving common corner cases.

You might have some highly-specific need which demands a particular tool, but it's likely that you're best accepting whatever is most popular in your chosen ecosystem (gtest for C++, nose/tox for Python, etc).