Hapimag has already been mentioned. For a time, they gave some inventory to DAE Europe, but otherwise their system has always been internal. Back before the RCI takeover, DAE Europe was itself a great option if you lived in Europe. They were a franchise of DAE, and much of their better inventory in Europe never showed up on the US site of DAE. You had to live in Europe to have a membership through the European office of DAE.
You did not mention what country you live in, but if it is the UK, you might want to check our UKRE, which only handles exchanges in the British isles. To use them your deposit also has to be a week at a resort in the British isles.
The old Swedish based Timelinx would have once been a good option in its day, but the people who bought the company did away with its timeshare exchange business years ago. Timelinx was the first timeshare exchange company to make use of the internet, putting their exchange inventory online.