Check what nifs use a texture: Sky

textures\sky\CloudsClear.dds

• meshes\sky\clouds.nif

textures\sky\CloudsCloudy.dds

• meshes\sky\clouds.nif

textures\sky\Oblivion_Sky01.dds

• meshes\sky\clouds_oblivion.nif
• meshes\sky\stars_oblivion.nif

textures\sky\RainDrop.dds

• meshes\sky\rainheavy.nif
• meshes\sky\rainlight.nif

textures\sky\RainSheet.dds

• meshes\oblivion\gate\oblivionarchgate01.nif
• meshes\oblivion\gate\oblivionmagicgate01.nif
• meshes\oblivion\gate\oblivionwargateani02.nif
• meshes\sky\rainheavy.nif

textures\sky\SkyNebula01.dds

• meshes\sky\stars.nif

textures\sky\SkyStars.dds

• meshes\sky\stars.nif

textures\sky\SkyStars01.dds

• meshes\sky\stars.nif

textures\sky\SkyStars02.dds

• meshes\sky\stars.nif

textures\sky\SnowFlake.dds

• meshes\sky\snow.nif

textures\sky\SunBeam01.dds

• meshes\idleobjects\ascensionparticles.nif
• meshes\oblivion\gate\oblivionwargateani02.nif
• meshes\sky\sunbeam01.nif
• meshes\sky\sunbeam02.nif
• meshes\sky\sunbeam03.nif