You just need some simple things like I show here.
Specific values will depend on the parts you want to use.
For single LEDs, 270 ohm resistors.
For switches, 10K pullup or pull down resistors.
For relay not needing much current, maybe a 2N2222, NPN type transistor. Can switch 5V or 12V coil in a small relay, bunch are listed here:http://www.dipmicro.com/store/index.php?searchStr=relay&act=viewCat&Submit=Search
Don't forget a diode across the coil.
If using larger current coil, then find a logic level N-channel MOSFET instead.