One of the best Young Avengers stories is 'Young Avengers Vol. 1: Sidekicks'. It introduced the team in a really engaging way. The characters like Kate Bishop and Teddy Altman were brought to life with great character development. Another good one is 'Avengers: The Children's Crusade'. It delved deeper into the backstories of the Young Avengers and had some interesting plot twists involving Scarlet Witch.
It's hard to give an exact number as new issues keep coming out. But as of now, there are quite a few series and one-shots featuring the Young Avengers.
I don't know for sure. Maybe you can follow some comic insiders or fan communities on social media to get the latest rumors and speculation about the return of the Young Avengers comics in 2018.
The Black Widow appeared in the movie 'The Avengers'. She was a character from Marvel Comics, played by Klingon Si Roze (K Desert). She was an agile agent who was proficient in a variety of weapons and fighting techniques. She often carried out dangerous missions and was one of the important members of the Avengers.