Toggle Latch

There are two Outputs and one of them is always ON. Send a Redstone signal to any of the Inputs to swap the Outputs. You can also manually right-click this gate to swap Outputs.

RS Latch

This gate has 2 Outputs. Each output has their own selector. Send an Input to that selector and it will turn the output ON, and it will remain on, until the other selector recieves and INPUT. Shift Right-click with a Screwdriver to switch modes. In Mode 1, the selectors also Output a signal, while Mode 2 does not.

Multiplexer

When you place this on the ground, the side facing away from the player is the Output, and the side facing towards the player is the Selector Input. When the Selector is NOT POWERED, the Output depends on the RIGHT SIDE. When the Selector IS POWERED, the Output depends on the LEFT SIDE.