I've been playing with my translucent PETG and it's Very Fun; if you print it hot, slow, and with no cooling it's Quite Clear, and if you take the time to sand and polish that down, it's nearly a window:
If you just treat it like regular PETG but use an aligned 100% infil the results are still Very Cool, as evidenced by the gargoyle in the photo. If you use less infil the effect is less pleasing, as you can See the Infill and it's not too pretty. Making something that could work with 0% infil might be pretty interesting to try. I tried doing another gargoyle using the Extra Slow, Hot, and Squished settings but it's just not dimenionally accurate enough to work well, as the hot filament leads to quite a bit of bulging. I'm told there's a floor polish that works as a brush/dip clear coat for plastic models I'd like to try with all of these--I think it would result in something even clearer.