Heyo! I've been a supporter of Glass8 for quite some time now, to the point where I would usually delay updating Windows 10 until Glass8 was ready as well. But seeing as BigMuscle has gone MIA (which I totally respect, life happens), I decided to look for a legitimate alternative that I felt fit the look and feel of what Glass8 was going for. I tried a Windows 7 theme for WindowBlinds, which looked great, but WindowBlinds caused my quite overpowered computer to lag quite a lot.
Recently, within a post on this very sub-forum, I found a theme for Stardock Curtains called "Eleven Seven". I checked it out, but found a few issues with it that I really wanted to fix. I thought the rounding on the corners didn't look sharp enough, the forced blue color made blending it in with non-blue backgrounds was impossible, among a few other things listed in the download page.
Thankfully, Curtains is PNG based, so modifying the issue I had wasn't a big deal. I feel I've modified it to the point where it's worth sharing with others. Full credit to atslah01 for the base theme. All I did was make a few changes here and there to touch it up. I also use "StartIsBack++" and "OldNewExplorer" to further push Windows 10 towards a Windows 7 look.
This theme does not have blurring behind the Window frame, because Curtains as a whole lacks that feature. If that's a deal-breaker for you, then I wouldn't recommend Curtains themes at all. I THINK Curtains might also lack the feature that allows for the glassy looking reflections to move behind the window frames, which is a distinctive look of Windows 7, but I'm not absolutely sure if that's the case. If I ever figure out if that's possible, I'll also try to modify the theme with it. I've gotten used to the differences though, and find that by setting the color theme to a light-ish gray, the benefits make up for the lack of blurring and lack of the glass movement reflection effect. It sure beats the stock Windows 10 look by miles IMO. Hope you enjoy, and hope this helps hold people over until BigMuscle returns, if he does. Wish him all the best!