You can find the most commonly used HTML symbols on W3Schools (see the related links.)

That said, you can actually use the decimal and hexadecimal version of HTML entities to produce any character available to you in the ISO-8859-1 or UTF-8 character sets. In other words, if you want the letter "a" you can get it using the HTML entity a

Because of this a complete listing is going to be very hard to find.

Use the HTML character entity ™ (preferred) or the character decimal code ™ or the character hex code ࡊ.

Use HTML Character entity ® it is a logo used for indicating registered and tradmark.

Every HTML tag starts with a less-than sign, as shown below.