Let's create a simple Xmas hologram. What would you need is a 3D printer, Acrylic Sheet, and CNC router or optionally a modelers knife if you don't have one and a soldering gun or station.

Electronic parts that would be needed are following:

bright white LED e.g. 504WC2E-W6-3PC
00 ohm resistor
18650 chargeable battery (3.8V)
CL 5V Micro USB 1A 18650 Lithium Battery Charging Board
couple of wires
18650 battery case

and optionally a Mini Rocker Switch SPST ON-OFF S654

Other material

acrylic (plexi) sheet of 2 mm thickness

Step 1: 3D Print

Firstly you would need to print the base for battery and the LED light. Use the STL or GCODE files above. You can find and option with or without a switch. Chose based on your preference.

Advantage of a solution with a switch is that the light can be switched off without need to remove the battery.

Step 2: Wiring

Secondly you would need to solder the component together and place them in the case.

Connect battery case to B+ and B- contacts to the charging board (+ to +, and - to -), optionally interrupted by a switch (solder in the case, if you do outside you would not be able to push wires thru)

Then continue with resistor and LED to OUT+ and OUT-. If you are not sure how to connect LED properly, check the LED and you will see a flat place by a contact that's supposed to be connected to negative battery end. (easy to remember - indicates the flat side ;))

Place all connected parts into prepped position in the case and feel free to charge by any charger with USB B mini connector.