We can see the tiles have square like shape.
The transformations, that could have been used in the design of this square tile is the reflection across a vertical or horizontal line through the center of the tile.
Also a 90° rotation clockwise or counterclockwise about the center could be used
Reflection over either diagonal could also be used
Translation of the upper left square to right, then down, then left could also be used
Therefore all of the above transformations could have been used.
ANSWER:
All of these transformations