There are a bunch of ways to move between macros in Keyboard Maestro, other than the obvious one of clicking on a macro group and then a macro within that macro group.
At the top of the Keyboard Maestro editor window there is a clock () icon button. If you click on this you will toggle between the last two macros you have edited. If you click and hold, you can select from recently edited macros.
Near the clock icon button are a backward (<) and a forward (>) icon button which will step backward and forward through the most recently edited macros. Clicking and holding on them will show you the recently edited macros before or after the current macro in the sequence.
There is also a command key cloverleaf (⌘) icon button which will take you to the most recently used (ie, triggered) macro. Similarly, clicking and holding will show you the other recently used macros.
In the View menu, there is a Select Macro submenu which includes options for Last Used, Last Edited, Previous and Next Edited, and all the recently edited or used macros. There is also a menu command to select the macro By Name, which will use the familiar Spotlight-like facility to choose a macro to select based on its name.
You can also edit a macro by holding the option key down while triggering it via a Macro Palette or the Status Menu.