The ST Micro L7805CV is a 1.5A, 5V positive linear regulator. It is the stronger older brother of the 78M05 but ironically it is the same size and shape, go figure. It may look like your everyday 7805 but looks can be deceiving!
Sometimes, voltages collide. When you have parts that expect/speak at different voltage levels, you have to build a mediator to smooth things out. This SparkFun BOB-10403 uses PCA9306 two-channel bidirectional voltage-level translator on a nice, small breakout board.
The DE-SWADJ is the adjustable version of the "SW0XX" step-down voltage regulators. Using the same form-factor as a standard 78LMXX style regulator, it is a much better way to give regulated voltage to your project.
The AnyVolt DC-DC converter is small, powerful, and very useful for applications needing efficient voltage switching. The guys as Dimension Engineering know their stuff!
This switching regulator lets you power circuits with higher and lower than the voltage of your power source!