Here are some great attribute filters I found for search results at endless.com.
1. When filtering by manufacturers, for example, instead of of clicking on a manufacturers name, you fill checkboxes near the manufacturers name. The great benefit of this is that you can filter by more that one manufacturer in the results.
2. When you keep on filtering, the option that become unavailable become grayed out, instead of disappearing. For example, if you choose a size 14 shoe and there are no more of this size from ECCO, the ECCO option becomes grayed out. The improved experience is obvious.
3. Choosing colors by actually seeing the colors, instead of words representing the colors. You can also choose more that one color, each one becoming circled. Here too, if a color is no longer available, it becomes half full. (It can’t just turn gray.)
4. Size options are in small squares, instead if a list. (This isn’t always possible, though.)
5. Narrow by price is more precise and saves space. A bar which you pull from both sides for minimum and maximum price is exact.
An organize wiki page for the suggestion would be a great idea for all of us (if it wasn’t done yet).