Square 1 is currently bundled with SONAR.
Pentagon I was never released for free but was bundled with SONAR for years. I suppose most that used it would still have access to it from a previous version of SONAR.
SFZ+ while given away for free for a limited time required a serial number so Cakewalk used their store to fill requests for the plug-in. Those who took advantage of the free offer or purchased the synth should have the download in their store accounts.