CustomHud is a highly configurable variable-based text HUD. While there's mods that also add text HUDS or allow you to customize the F3 debug screen, they aren't fully customizable, their customization is mostly limited to colors and if a line/module is displayed or not. CustomHud allows you to put the data exactly where you want (in addition to full color support, including hex), and it does it with a "variable" type system.

In the profile file you write what you want to see and use "variables" like {fps}, {version}, {facing}, {memory_used}, etc where you want them to be.

It also supports "conditionals", where depending on the output of a variable you can pick what you want to show. {vsync} for example produced "true" or "false", and when used in a conditional like {{vsync, "(vsync)", ""}} then if vsync is true, it'll display (vsync) but if it's false, then it'll display nothing.

Here's a full example:

CustomHud Example Output

The config that produced it:
Customhud Example Code

For a look at all of the features that CustomHud offers, like putting info on all 4 corners, changing the background color, a better look on variables and conditionals, and more, check out the project's wiki on Github.

This is a Fabric Mod, there's no plans for a Forge port, but the license allows you to port it yourself if you wish.