Question: I know that in a previous version of Minecraft, you could get a Ender Dragon spawn egg (a white egg, like it has no texture). Is that still possible, and if how do i get it?

Answer: 
As of 1.19.3, you can now obtain them with the `/give` command.
You can also type '/give 383 1 63'. It'll give you the white egg with grey spots.
It is avaliable on any version below 1.7.5

Example:
 /give Popcorn98 383 1 63