Matlab: How to obtain all the axes handles in a figure handle?

Use FINDALL:

allAxesInFigure = findall(figureHandle,'type','axes');

If you want to get all axes handles anywhere in Matlab, you could do the following:

allAxes = findall(0,'type','axes');

EDIT

To answer the second part of your question: You can test for whether a list of handles are axes by getting the handles type property:

isAxes = strcmp('axes',get(listOfHandles,'type'));

isAxes will be true for every handle that is of type axes.

EDIT2

To select only axes handles that are not legends, you need to cleanup the list of axes (ax handles by removing all handles whose tag is not 'legend' or 'Colorbar':

axNoLegendsOrColorbars= ax(~ismember(get(ax,'Tag'),{'legend','Colobar'}))