I don't have any answers as to the type of eggs, but am curious as to where your background is. The picture is from the back of the tank, right? Is your background inside or outside your tank?
Well, most people put their backgrounds on the outside. I'd expect that having a background on the inside would create a pocket of space that is hard to get at and clean, plus I'd worry that the background would disintegrate over time, and leach pigment and chemicals into the water.
****... i'm lookin like an idiot lol... i think i'm gonna go and hide myself.
when i bought the background i saw that it wasn't a normal paper and was very slippery to water so i thought it was resistant to be inside the tank so the view would be more natural and brighter.
At first before I saw the pic I thought pond snail eggs. Now I see there are way too many to be those, pond snails lay eggs in small clumps. If I had to guess, I would say they are danio eggs that were laid by a fish swimming behind your background that settled onto the plastic, explaining why so many survived and were not eaten. Out of sight out of mind (and mouth). Let us know what you get when they hatch.