Tianyu has lab stones and has cut traps in other materials, you might try contacting them. Ouros Jewels also has a lot of value grown side stones but I’m not sure about traps. Here are two current threads about side stones that might help in your search:
You can try Neo Lab Diamonds. They are based out of Toronto and have a selection of matched pairs - mostly in high colours. Maulik there is lovely to deal with.