What shard are you on Mikni? I know on Atlantic the deco items seem to sell really well. The cannon (7th year), wall banner deed (9th year), decorative tree stump (7th year), and the character statue makers (6th year) all sell well. The ethys/polar bear also sell well but chances are you won't get as much for them.
I believe the average on a polar bear is tops 4.5 mil where as you get atleast 6 mil for a character statue maker and as much as ten for a cannon.
There are sites that allow you to check the current pricing of such items in Luna. I would check out what some of these items are selling for on your shard, pick the one that is selling for the most and offer it a little lower than is the current average in Luna.
Some things that don't sell for a lot right now are vet robes/cloaks and dye tubs.
Hope that helps and good luck!