I remember previously using Blue Cat Audio plugins with a much earlier version of Sonar and I like the plugins. I recently discovered their website again and decided to used one of their plugins and it worked well for me.
On their site, there are several great plugins that might be of used to the Sonar community.
Renumber to take advantage of the FREE ones.
The Blue Cat pack itself comes with 7 plugins.
BLUE CAT FREE PlUGINS Bundle (Click Win X64 VST3 on the right side, or the appropriate option to download).