If you want a bunch of new maps to try out you can get the Mega Map Pack here(torrent):
http://induktio.net/wiki/Mega_Map_Pack

or a mirror here

http://www.gamefront.com/games/swat-4/addons/mega-map-pack

If you use the first link(infuktio) there are some extra maps in the second link below the "newest version" link on that page that don't seem to be in the mega pack.

Here is another gathered map collection someone did:

https://hjorslev.com/download-swat-4-maps-9.html


Maps may overlap between the two.