Most Redstone Components & Other Transparent Blocks can be placed on any side and type of pistons. Sometimes in certain situations can cause trouble with interactions.

• Comparators, Repeaters;
• Redstone Dust;
• Any Type Pressure Plates;
• Any Type Torches;
• Flower Pots;
• All Types Rails;
• . . .

Powered (Activated by Player / Item) Pressure Plates cannot be moved or destroyed by Pistons, neither facing up / down / sideways.

Un-powered Pressure Plates, Flower Pots, Torches, Comparators, Repeaters and Rails are destroyed and dropped if there is interaction with the piston.