That hopefully isn't just a screenshot

Any ideas?

It is unfortunate that the vanilla "ready" indicator already includes a plus, but I was thinking that with more pronounced colors.

Something like this?

Oh damn, that looks good. Not sure if I'd be tacky, but maybe have the + be gold?

Sure.

Hmm, now that I'm at my pc, I'll try a more yellow-gold, and depending on how that looks, I'll either use that, or the green one

Okay, this is will be the icon. I added more spacing between the sword and plus (4px), and then moved the whole thing up (2px). And thanks to tinypng, it's only 232 bytes!