Tile coloring

How can you change the colour of 1 tile?

I don't believe that changing one is possible... but someone may have a way.

You can create your own tile:
How to Create Custom Start Menu Tiles in Windows 10
- see Better StartMenu

(Yes, that's a 3rd party program and you didn't specify whether using one would be ok).

There's also:
Win10Tile - native, custom Windows 10 tiles with jump list and context menu
Win10Tile: Create Custom Start Menu Tiles In Windows 10

Possibly not a 'finished' tool.

You can give TileIconifier a go if you want: Releases . Jonno12345/TileIconifier . GitHub

It will allow you to pick the colour of your choice for the tile background, or just select a transparent one should you have an image you want to use that has no background. You can also alter the positioning and zoom level of whatever icon you're using for them.

Do be aware however that some start menu shortcuts cannot be altered in this way due to wherever they're shortcut from. A simple browser shortcut from a typical folder can be altered for example but if that browser is installed via Microsoft Store it won't appear as customisable.

Here's an example of some shortcut icons I've created alongside the UI of the program.