These supported tags come from the WordPress.com code FAQ.

Address Tag1

Infinite Loop
Cupertino, CA 95014
United States

Anchor Tag (aka. Link)

This is an example of a link.

Abbreviation Tag

The abbreviation srsly stands for “seriously”.

Acronym Tag (deprecated in HTML5)

The acronym ftw stands for “for the win”.

Big Tag (deprecated in HTML5)

These tests are a big deal, but this tag is no longer supported in HTML5.

Cite Tag

“Code is poetry.” –Automattic

Code Tag

This tag styles blocks of code.
.post-title {
margin: 0 0 5px;
font-weight: bold;
font-size: 38px;
line-height: 1.2;
and here's a line of some really, really, really, really long text, just to see how it is handled and to find out how it overflows;
}
You will learn later on in these tests that word-wrap: break-word;will be your best friend.

Delete Tag

This tag will let you strike out text, but this tag is recommended supported in HTML5 (use the <s> instead).

Emphasize Tag

The emphasize tag should italicize text.

Horizontal Rule Tag

This sentence is following a <hr /> tag.

Insert Tag

This tag should denote inserted text.

Keyboard Tag

This scarcely known tag emulates keyboard text, which is usually styled like the <code> tag.

Preformatted Tag

This tag is for preserving whitespace as typed, such as in poetry or ASCII art.