[Note: This is an unfiltered list of sites that appear to be on-topic.No attempt has been made to confirm the information on these sites.]
[Note: these are sites that touch on subchasers and related topics, including some of the other ships that were engaged alongside of chasers and so on.]
John Beech's Austro-Hungarian Navy Homepage
Information on fighting ships, including some that were engaged in areas where chasers worked. This is a site to look at if you are studying the fleet that a particular chaser was a member of.
The National World War I Museum
Web site of the memorial and museum in Kansas City, dedicated to the men and women who served in WWI. The archives includes a collection of submarine chaser photos donated by the daughter of Boatswain's mate, 2nd class, Stephen W. Ostrander. The collection is accession number 2003.9.