I'm testing out some new backgrounds.

Not sure if I like the diamond shape since I couldn't make it a seamless tile.

I made the cell padding 5 for the diamond background so it looks more like a thin border.

I need to do some more experimenting but in the meantime, I'll explain how I made the outside and inside border.

First open a new transparent canvass 100x100 pixels.

Flood fill with a color of your choice. I used #bdccd3.
Go to Effects>>Texture effects>>Tiles and set to default.

Once you're on the default settings, change the Tile shape to Triangle and Tile size to 8.
All other settings are the default.

Click ok.

That's it.