Just some early/mid-game smelters. Should cover all your needs: There's in-line and counter-flowing smelters, and two fuel-line directions (CW/CCW). If it's not a big hassle, I like to put roboports in my smelters, so you're stuck with that! Alongside the 'basic' smelters (the ones you basically see everywhere), there's compact smelters with a smaller footprint.
The designs are certainly not my own.