Texture packs are collections of images used by cell machine remakes to change the game's textures, especially those of cells. These packs can aim to improve the user experience by making cells look better and, or potentially more functional. Functional texture packs achieve this by increasing contrast between cells, often through distinct shapes or colors, or including the subtick order in the cell's sprite.
Typically, texture packs use 16x16 resolution for cell sprites, but most remakes support higher-quality sprites, which might cause performance issues on less powerful machines.