Finishing College with Employable Skills
The kinds of things suggested in your question and many similar things won't help them. Learning some other "tool" or "language" or "technique" at a beginners level will still leave them with just a bunch of tools they don't really know how to use. 

Instead give them a project - preferably a hard project - in which they can use what they have learned, but which also likely forces them to learn at least one new thing. Moreover, if their goal is employment, make it a team project so that they get the experience of working closely with others. 

If you can make it a real project, not just an academic exercise, all the better. 

Also, make them use some proven methodology, not just hack together a solution. My suggestion would be Extreme Programming, since it is completely defined and has good personal practices within it. It would give them good guidance for a first such project. Scrum, being a bit more general might leave them without the guidance they need, hour to hour.