The LM2596 is a commonly used popular step-down switching regulator IC. The adjustable version can take in input voltage from 4.5V to 40V and convert it to variable voltage sourcing upto of 3A of continues current.
LD1117 is a Positive Voltage Regulator with a very low Voltage drop across it. Based on the version of the IC the output voltage can vary between fixed voltages like 1.2V, 1.8V, 2.5V, 2.85V, 3.0V, 3.3V, 5.0V or can also be a variable voltage regulator.
The TL431 is a regulator diode whose output voltage can be programmed by changing the value of resistors connected to it. It acts almost like a Zener diode except for that the voltage rating of this IC is programmable.
The HLK-PM01 is a small size low cost AC to DC converter which can take in 110V/220V AC at 50/60 Hz and give 5V 3W output. The module is can be used in designs which run on 5V and needs to be powered form the AC mains.