If you intend to use UnityEx for learning or modding, never share the extracted files publicly.
Some sites claim to offer a "free download" but require you to first purchase a subscription to a file-hosting service. These are . The actual tool is freeware; you should never pay for it.
UnityEX - Вскрытие игровых ресурсов - Zone of Games Forum
Select the assets you want. Go to Export > All Assets to save them to your hard drive. For 3D models, ensure "Export as FBX" is selected.