Witches, Wizards and Evil Faries
It is unknown.
The collective noun for curses is often referred to as a "litany" of curses. This term captures the idea of a series or list of curses being expressed together. Other terms like "heap" or "string" of curses can also be used informally, but "litany" is the most commonly accepted.
Avada Kedavra
There are none.
Count Your Curses was created in 2011.
Satanic Curses was created in 2007.
Water Curses was created in 2007.
Curses and Countercurses is in Chapter 12, Moment 2 (Christmas at Hogwarts), lying on the bench.
Generational curses are those curses that do not end when a person dies. They are curses that follow the children, grandchildren, and great grandchildren of those who were cursed. They are passed on from one generation to the next.
There is a lot of information about curses found on the internet. Wikipedia has tons of information on curses as well as sites like How Stuff Works. Of course there is no scientific evidence for curses.
Curses - video game - was created in 1993.
Curses - video game - happened in 1993.