My accessories at the moment include webbed gloves and mask-goggles.
Attachment 28707
(Photo from a Vancouver Mermaids meetup, hence the watermark/ Pic is from Courtney Mermaid)
I also have a conch trumpet that I made out a shell I got for cheap at a farmer's market. (hopefully get some pics of that this summer). Next goal: a decorated boat-hook weapon, to get away a bit from the traditional trident. (something kind of like this )