How many types of Meta Tags are there in SEO?  What are their characters limits?

Hi Friends,
Some important meta tags that one must use in the webpage are:
1. Title Tag: <title>The title of the Page</title> (Unique title for your page)
Limit: Google typically displays the first 50-60 characters of a title tag, or as many characters as will fit into a 512-pixel display.

2. Description Tag: <meta name = "Description" Content="Description of the Page">
Limit: Roughly 155 Characters

3. Keyword Tag: <meta name="Keyword" Content="Your Keywords">

According to Google they didn't look at meta keywords then you will be surprised that why I am mentioning it here. It is here because 'Yahoo' search still use these in their SERP. So don't miss it because still have 28% search share so why miss these 28%.

4. Robots Tag: <meta name="robots" Content="......, ......">
The valid values for Robots Meta Tags 'Content' attribute are: "INDEX", "NOINDEX", "FOLLOW", "NOFOLLOW".

Meta Description tag with 1200 pixels limits
Meta Keyword tag
Title Tag with 600 pixels limits
Meta Robots