[tokamak-teapot]

Lots of old documents with rules about writing ridiculously large parts of them in ALL CAPS. For no reason at all, that I can determine.

[Sanguinaire]

All-caps mode exists as a safe space for FORTRAN programmers.

[sbierwagen]

Notepad++ has a toolbar option that will uppercase all the currently selected text. Write a paragraph normally and then uppercase it with one click.

[tpxl]

Lots of tools have this. IntelliJ has it mapped to ctrl shift U by default I think.

[boogies]

In vim gU makes the selection/motion uppercase, gu makes it lowercase and ~ toggles each of its characters' cases.

[mangamadaiyan]

~