A tileset is a collection of tiles with interactions defined so they fit together in a logical way, typically following a common theme. They allow a builder to select from a list of different tiles (each with varying sizes) to construct an area in a module, but only one tileset may be used for each area.
Neverwinter Nights originally included 10 tilesets, and additional tilesets were included in the expansions — 3 in Shadows of Undrentide (SoU) and 5 in Hordes of the Underdark. A further 2 tilesets were made available in hak pak form from BioWare with the release of patch 1.67. These were integrated into the core game resources (removing the need for the hak pak) in patch 1.69, and at the same time 6 more tilesets were added, bringing the total number of BioWare tilesets to 26. Moreover, certain groups and individuals have released — and continue to release — other tilesets for the community to use, providing unlimited selections for a module builder (although there is a practical limit on how many tilesets can be used in a single module). Most notable of these groups are the Community Tileset Project (CTP) and the Community Expansion Pack (CEP). (All CEP tilesets require CEP version 2.2.)
barrows (TBW) (1.69)
The letters in parentheses after tileset names are the codes needed by custom content makers when referring to these tilesets.