Virtually all agencies will place scrub techs. It is really all about the openings posted at hospitals they have contracts with. If your agency doesn't have scrub tech openings, I'm going to guess they are rather small. Try a larger agency. Certain agencies may be more OR friendly than others, including those started by OR staff. First Assist comes to mind (I worked for them for several well paid years), as does Surgistaff (Northern California above San Francisco only), and The Surgical Staff (worked for them in Seattle). I worked for years for OR Support that was started by an OR tech (now gone). I get a lot of emails from OR Travel Nursing (ortravelnursingjobs) which is really a name of PPR, an agency that gets rave reviews for service (but pays less generally) - I did work with them once. But generally, these smaller agencies have fewer jobs. But they at least speak the lingo.
The only scrub tech forum I know of is AST. I would certainly hope that AllNurses welcomes techs. Generally (not wanting to raise controversy here), scrub is considered a nursing specialty rather than the more technically accurate allied health. So you would go to nursing travel agencies, not allied health travel companies for the best results. And to discuss OR practice, nursing forums should be the best place (other than perhaps AST) and AllNurses has the largest surgery forum I know of.