2DA

Yeap, 2DAs are still in the game. Stands for "Two Dimensional Array", it's a text file that contains information that the game needs to handle some aspect of its functions. 2DAs are very easy to edit*, you just need a simple text editor, like Notepad that comes with Windows, change some of the contents, save the changes, putting the new file into override, and fire up the game to see the results. 2DAs are used in Infinity Engine games like Baldur's Gate as well.

Warnings
 LABEL               STRINGREF      MODEL 746 Creature            46656          c_creature 746 "Some Creature"     ****           c_somecreature 747 Some_OtherCreature  46657          c_othercreature 
 * Make sure any tabs you use are converted to spaces instead.
 * Columns are NOT important, they're done that way to make it easier for us to read. As long as there's one space between the entries, NWN will read them just fine.
 * However, you can include spaces in some entries by encasing the label in quotes, which are used in labels often to skip requiring a StringRef in a TLK i.e.
 * 2DA changes are based server sided. 2DA changes are overridden by the server in a multiplayer session if you're client. If you're the server in a multiplayer session, you'll override all client's 2DAs.
 * 2DA hakpacks override 2DAs in the override folder.

List of 2DAs
However, there are more 2DAs, but this are the most essential ones.