Hey! Thanks for asking, I looked into this because I wanted to be sure before promising anything.
From what I found, itch.io bundles don’t seem to grant previous buyers access to new packs added to the bundle later. So it's a bit of a bummer if you eventually want all the icons, since buying individually would be more costly.
So I was thinking of a way to make it more convenient to you guys, and here's what I landed on:
While I'm working on a set of icons and the whole bundle isn't finished, I'll leave the individual packs at a 50% discount. And when I finish the batch, I'll bring back the packs to full price, and open the 10 pack bundle for 14.99 (Which is also a 50% discount).
This way you guys can benefit from the bundle discount when buying individually, without having to wait for the bundle, and you can even pick and choose which pack you like, before they go back to full price once the bundle is finished.
Hope that makes sense, and thanks again for asking — it helped me catch this before making the setup confusing.