If the textures look blurry even after installing the pack, go to Settings > System > Language and ensure the emulator language matches the region of the texture pack (usually English/US). Mismatches can cause the game to fail to load the new textures. Sm-g900t Custom Rom File
Here is a useful breakdown of the best packs and how to use them. Why it’s the best: The PSP version of Tekken 6 is widely considered the most stable for texture modding. The community has done an incredible job upscaling textures to 4K or 8K quality, making the game look almost like a remaster. Download Umt Dongle Smart Card Driver 1000 Success -tested- Site
Since you didn't specify which platform you are playing on (PC via emulation or a modded console), I have compiled the best options currently available. The vast majority of "HD Texture Pack" development happens on the PC emulator (for the portable version) or PCSX2 (for the console version), as the official PC port of Tekken 6 was notoriously problematic and is rarely modded for textures.