Some are quite interesting:

Filamentum's Flexfill 92A - this is a flexible material
PolyMaker's PolySmooth - this is a ridged material that can be polished with isopropyl alcohol to remove the layer lines. The results are quite nice!
Layfomm 60 - this a odd one. when it prints it is ridged. but when you soak it in water, it dissolves some component of the material and what remains is very soft and squishy.

I've also printed some more "standard" types of filament with good results:

colorFabb_HT, which is a high strength, high-temp material
some PETG filaments
Kodak ABS
Kodak PLA

I have another one on order I am quite excited about: Polymaker's PolyCast which is meant to be used for investment casting, which is another one of my more recent hobbies I've acquired. It is supposed to be "ash free" meaning when you pour the molten metal into the form, the object burns away to to virtually nothing. This material is also supposed to be polishable like their PolySmooth