Add lava lamps to vanilla Minecraft

To obtain them, pick a stained glass block of your color of choice, rename it on an anvil to "lava lamp" or anything similar, and you'll get its respective lava lamp color.

Then you can place it on a glow item frame on the ground to display it in your world.

As a tip if you plan to use many, you can rename a stack instead to save on enchanting levels.