HTML standards are maintained by the World Wide Web consortium (W3C).
You can find all you need to know about HTML through the work of the W3C.
Tutorials and reference for about any language can be found for free through W3 Schools.
In particular, find tutorials for HTML here, examples of HTML here, and a reference set of all the tags here.
Here are the tags we've learned so far:
html
head
title
body
a (href attribute)
br
p
ul,ol, li
img
h1, h2, h3, h4
b
i
u
em
table
td
tr