I often need to browse folders full of STLs, and I was dissatisfied with the performance of most programs. So I wrote one myself where you can quickly skip to the next file with right arrow key.
First update: Some users requested a color change (too little contrast in gray), so you can now customize it via View -> Select Default Material. Others felt the mouse wheel zoom was inverted (a common source of disagreement), so you can customize this as well: View -> Flip Zoom. Thank you for testing so far! There’s more to come!
Second update: https://papas-best.com/stlviewer\_en This greatly improves rendering quality on high-DPI displays. It also fixes a few UI glitches. I’ve listened to the complaints about the installer (no feedback, is it hung or has it crashed?) and so it comes with a proper setup dialog now