I wanted a soap dish with minimal surface-area contact with the soap bar to allow/promote air-drying and minimize the "goo" that often results if a bar is kept wet. I didn't really care about drainage since air-drying was sufficient, and for me the soap dish is "disposable" and replaceable. Since this was for use in the shower, I also wanted "feet" on the soap dish so that any water underneath could air dry.

I whipped this one up, which is essentially a matrix of little cones in a rectangular tray. It's a good test of your 3D printer for good bed adhesion. By printing it upside-down (with feet up, printed near the end), I didn't find I needed any supports. When printing with PLA, I found a hotter-than-usual hotend (240°C) and bed (70°C for initial layer), as well as a good wipedown with isopropyl alcohol, allowed me to print all the little inverted cones without them toppling over. A slower-than-usual first layer speed also helped. I also found that with 100% infill, the transition from printing cones (up to 5mm) to the base (layers above 5mm) went without issue. There was minimal stringing, which I could live with (or quickly blast off with a heat gun, if it did matter).

Indeed, if you're wrestling with good bed adhesion, you'll find this a bit frustrating to print, and scraping off lots of little crumbs may create a small mess. But master this, and I think it'll go a long way to helping you master getting that perfect first layer.