You should think this through again and clear up your definitions. First you state that "Closed Openings" are anything other than 1.e4 (which is not what people usually use it for), then you surprise the readers by declaring that "Flank Openings" are anything other than 1. e4 and d4. Other categories also overlap again and again, the whole thing is quite chaotic. Any beginner reading this will be more confused that helped.
How many types of Openings are there? (For Beginners)

You're right, and I apologize for any confusion caused by the previous response. I appreciate your feedback, and I'll provide a revised and clearer explanation of the different types of chess openings later...

Chess Openings Resources for Beginners and Beyond…
https://www.chess.com/blog/RussBell/openings-resources-for-beginners-and-beyond
https://www.chess.com/blog/RussBell
There are numerous types of chess openings, each with its own characteristics and strategic goals. It's challenging to provide an exact number since new variations and approaches emerge over time. However, I can give you an overview of some of the most common and well-known types of chess openings:
Open Games: These openings begin with 1.e4 (moving the pawn to e4) by White, and typically respond with e5 by Black. Examples include the Ruy Lopez, Italian Game, and Scotch Game. Open Games aim to establish a balanced and open position with an emphasis on piece development.
Semi-Open Games: These openings begin with 1.e4 by White, followed by a move other than e5 by Black. The most famous semi-open game is the Sicilian Defense, where Black responds with c5. Semi-Open Games often involve tactical battles and dynamic pawn structures.
Closed Games: These openings involve moves other than 1.e4 by White, resulting in a closed center. Examples include the Queen's Gambit, King's Indian Defense, and Nimzo-Indian Defense. Closed Games focus on solid pawn structures, strategic maneuvering, and positional play.
Indian Game: This category encompasses various openings like the King's Indian Defense, Queen's Indian Defense, and Grunfeld Defense. Indian Games typically involve the fianchetto of the bishop on the kingside or queenside by Black, aiming for flexible pawn structures and counterplay.
Flank Openings: These openings, such as the English Opening and Reti Opening, involve moves other than 1.e4 or 1.d4 by White. Flank Openings often emphasize control of the center indirectly, focusing on piece mobility and flexible pawn structures.
Gambit Openings: These openings involve sacrificing material, usually a pawn, for rapid development or other positional advantages. Examples include the King's Gambit, Queen's Gambit, and Benko Gambit. Gambit Openings aim to create dynamic positions and seize the initiative.
Irregular Openings: These openings don't fall into well-established categories and involve unusual or unorthodox move orders. Examples include the Budapest Gambit, Grob's Attack, and the Polish Opening. Irregular Openings can lead to unique and unpredictable positions.