Resource Pack HUD (otherwise known as RPHud) gives content creators the ability to mess with the in-game HUD without needing to write their own standalone mod. This is accomplished through the execution of RPHud scripting files, which are loaded from resource packs. Using the simple, quasi-functional language, it's easy for anybody with a rudimentary grasp of algebra to build a HUD like this:

Recreation of a Fallout HUD

I'm a user! How do I use RPHud-enabled packs?

Just about the same way you would use any other pack. Equip any RPHud-enabled pack, and the uppermost pack with RPHud support will be used to augment the HUD.

Where can I find some RPHud-enabled packs?

I'll probably build an index of RPHud packs if enough people are interested and enough packs are created. For now, though, you can find a few packs here:

I'm a content creator! How do I make RPHud-enabled packs?

Most of what you need can be found on the wiki. Also available is a Visual Studio Code extension that enables syntax highlighting and completion for RPHud script files.