The Synology Download Station is a great application for downloading torrents but sometimes it's unable to find the things you are looking for.
It happened to me and as I was looking through the settings for a way to add a search engine I found out it has to be a .dlm file. I don't know when this was changed but I remember that I could just add a URL but ala. So I was searching for .dlm files when I encountered the SynoBoost website.
The SynoBoost website has more than 30 search engine files waiting to be downloaded. About half of the search engines require authorization but that still leaves a lot of search engines to add to your Download Station.
Credits to the SynoBoost project!
Detailed instructions on how to add the search engines can be found at the installation page. The page is a bit outdated due to the screenshots from a previous version of the Download Manager but you will get the general idea on how to add the search engines.
Happy DL and remember it's not about searching, it's about finding ;)