[5e D&D] Adding new Attributes to existing Sheet?

In the past I've had trouble customizing a existing sheet for my campaigns with adding new things like Attributes (such as for 3rd ed. D&D Sheets). Primarily in that the sheets would not display them or if they did rolls did not work and such. I was wondering if anyone could help try to find a way to add a new Ability Attribute and related things to a D&D 5e sheet such as the one made by Roll20?

You can add as many as you like without effort on the Abilities & Attributes tab. They just won't display on the sheet itself, and will need to be done on a per-character basis. But they can be referenced in formulas and macros. I believe the Shaped Sheet has the ability to activate Honor and Sanity as additional abilities.

The R20 sheet isn't publicly available any more. I think there's still a pretty old version on github, or there's the Shaped & Community sheets - are any of those useful? If you're not keen on customising a sheet, you could always do a quick & dirty version - use the resource tracking repeating section on the 5e sheet to add some custom Attributes. You'd need to make macros for the rolls involving them, though they won't be any more difficult than the rolls you'd have to create to add custom abilities to a sheet.