Besides registers and markers (see @phils's answer about both and my other, Icicles answer about markers), bookmarks, particularly either autonamed or temporary bookmarks, can be helpful for this. You need library Bookmark+ for these special bookmark types.
An autonamed bookmark is one that you do not need to name. It is quick to create and delete: just hit a key. The same key creates or deletes a bookmark at point. (By default, this is bound to
C-x p RET, but you can of course use any key.)Autonamed bookmarks are, like bookmarks in general, persistent. But you can optionally have them be deleted automatically.
You can also create temporary bookmarks or make any existing bookmarks temporary. You can, for example, choose to make autonamed bookmarks be temporary automatically.
You can quickly cycle among a given set of bookmarks. For example, to cycle among autonamed bookmarks, use commands
bmkp-next-autonamed-bookmark-repeatandbmkp-previous-autonamed-bookmark-repeat(binding them to keys).You can highlight bookmarked locations in different ways, so it is easy to spot them.