This is an item in the Lost Infinity Stones mod. It can be obtained by killing Prime Deviants:
Killing Prime Deviant Azross drops the Top Right Tablet Fragment.
Killing Prime Deviant Livorax drops the Bottom Right Tablet Fragment.
Killing Prime Deviant Kalikos drops the Top Left Tablet Fragment.
Killing Prime Deviant Zenon drops the Bottom Left Tablet Fragment.
Crafting all four tablet fragments creates the Deviant Homeworld Tablet (with no power).