How to list all Git tags?

git tag

should be enough. See git tag man page

You also have:

git tag -l <pattern>

List tags with names that match the given pattern (or all if no pattern is given).
Typing "git tag" without arguments, also lists all tags.

More recently ("How to sort git tags?", for Git 2.0+)

git tag --sort=<type>

Sort in a specific order.

Supported type is:

• "refname" (lexicographic order),
• "version:refname" or "v:refname" (tag names are treated as versions).

Prepend "-" to reverse sort order.

That lists both:

• annotated tags: full objects stored in the Git database. They’re checksummed; contain the tagger name, e-mail, and date; have a tagging message; and can be signed and verified with GNU Privacy Guard (GPG).
• lightweight tags: simple pointer to an existing commit

Note: the git ready article on tagging disapproves of lightweight tag.

Without arguments, git tag creates a “lightweight” tag that is basically a branch that never moves.
Lightweight tags are still useful though, perhaps for marking a known good (or bad) version, or a bunch of commits you may need to use in the future.
Nevertheless, you probably don’t want to push these kinds of tags.

Normally, you want to at least pass the -a option to create an unsigned tag, or sign the tag with your GPG key via the -s or -u options.

That being said, Charles Bailey points out that a 'git tag -m "..."' actually implies a proper (unsigned annotated) tag (option '-a'), and not a lightweight one. So you are good with your initial command.

This differs from:

git show-ref --tags -d

Which lists tags with their commits (see "Git Tag list, display commit sha1 hashes").
Note the -d in order to dereference the annotated tag object (which have their own commit SHA1) and display the actual tagged commit.

Similarly, git show --name-only <aTag> would list the tag and associated commit.

To list tags I prefer:

git tag -n

The -n flag displays the first line of the annotation message along with the tag, or the first commit message line if the tag is not annotated.

You can also do git tag -n5 to show the first 5 lines of the annotation.

Also git show-ref is rather useful, so that you can directly associate tags with correspondent commits:

$ git tagosgeolive-6.5v8.0...$ git show-ref --tagse7e66977c1f34be5627a268adb4b9b3d59700e40 refs/tags/osgeolive-6.58f27e65bddd7d4b8515ce620fb485fdd78fcdf89 refs/tags/v8.0...