Hi, this is Chessking47 writing on tactical devices. I guess you know the basic forks, pins, and skewers, but there are more. First of all, the Clearance Sacrifice.
You might love to play a powerful move, but can't because one of your pieces are in the way. If this is hard to imagine, here's an example:
The queen would love to move to g7 but the rook is in the way. You have to take the rook out. Not 1. Rg8+?? because 1... Rxg1 proves annoying. However, 1. Rh7+! is better. 1... Kxh7 2. Qg7#! This was a sacrifice to let one piece go onto a square, but another "friendly" piece was occupying it. You had to sacrifice the piece!
Next, the decoy. You are forcing a piece to occupy a square it would not like to occupy. This powerful tactical device will be shown here:
Black would never play 1... Qb5?? 2. Nc7+. However, because white has the move, he can decoy. 1. Bb5! Pin and forced is 1... Qxb5 2. Nc7+ forking the queen, king, and rook. Note: Decoys can also be when a square is defended, for example, a mating square, and you want to kick the defender out.
Next, deflection. A piece is holding the position together, and to shatter the structure, you need to chase the glue away.
Then, we have the double attack.
A double attack is a discovered attack. 1. c4+ hits the king with the bishop, and the queen with the pawn. After the king moves, white gets back a queen.
Next, forks, pins, and skewers. Hopefully you know these, but if you don't, search up Beginner Tactical Devices.
My favorite was saved for last! The windmill. It's when normal checks are followed by discovered checks, picking up material. Look at The Complete Book of Chess Strategy by Jeremy Silman.