I'm using granulated sugar as my powder - it's much more IR absorbent than you'd think!
I'm using a variation of the High Speed Sintering process in BrundleFab, but using granulated sugar instead of nylon as the powder, and using black inkjet ink instead of pure carbon black.
Fine powdered sugar is actually more IR reflective than granular, in my experiments - you might want to use granulated in a 'classic' laser-based SLS.
When dealing with it, be sure to clean up any caramel that may form in your experiments. The caramel is much more hydroscopic than the granulated sugar, and goes from hard and brittle to a gooey mess in about a day.
If not sugar, if you are 'binder jetting', you can usually get away with some variant of plaster powder and rice wine or vodka.
If you are laser sintering - can't help you there. Nylon and sugar are the only materials I'm familiar with.
New to this thread, we make a fine PMMA (Acrylic) powder which we can supply in smaller quantities. I have a 45 micron media size, an 85 micron or 140 micron ex stock. Also can offer PA6 copolymer with PE 90/10) in a sub 100 micron powder which we can regrade to tighter fractions if there is some volume.
... if it's transparent for the human eye (not dyed or blended with carbon black), then you'll need a CO2-laser -- and 10Watts seems to be the smallest available types today ... when I've started my first tests with CO2 in 1989, my first CO2-laser was a "naked" tube with 1,5Watts, the next types were sealed RF CO2-lasers with 3Watts and 5Watts ... a more modern type last year was 30Watts ...
Dyed or black powder can be sintered, melted or even evaporated with a blue 2W-laserdiode ...