In Emerald, my first shiny was a common Shiny Zubat. I remember finding it in Victory Road, I think it was near the exit to the Pokemon League. I remember after Diamond came out, I used the Emerald Battle Tower cloning glitch to send a few Shiny Zubat to my Diamond game and I think I traded some away. I ended up losing my Diamond cart, but luckily because of the cloning glitch I still had it available in Emerald. I brought it up to Pokemon Home.

Around the same time, either me or my brother had found a Shiny Lunatone in Sapphire. I remember this distinctly because my brother has also mentioned it years later, but my brother asked me about the Lunatone and I said "Don't catch this Lunatone, we already have Lunatone in the box." In a few of the gen 3 games, there were dedicated boxes for my Pokemon and my brother's Pokemon so I think the Sapphire save file was a shared save.