Little things in Blender that could drive someone crazy. I have a lot of objects in the scene, some of them marked as restricted visibility. Before the render I want to "unhide" them all - not to search them one by one... Is it possible? It should be much more intuitive this kind of most obvious things...
Press A until everything is selected. If you have anything selected before pressing A you will have to press it twice, otherwise only once. (This will select the hidden objects as well so don't worry about them for now.)
Edit: As Mr. Zak pointed out in the comments section, it is unnecessary to select everything.
Press Alt-H to unhide everything.
You can also navigate to the
Object menu at the bottom of the View3D window, select
Show / Hide and select
Show Hidden. This may be helpful if, like OP, you have issues with the Alt key combination. Practically everything in Blender has a button somewhere.