The vast majority of my devices are Kasa devices.  I linked the Tapo app with the Kasa App and all of my devices showed up in the Tapo App.  I Uninstalled the Kasa app. 

I recently got a Tapo doorbell camera.  This is actually my first Tapo device.  I then added Tapo to Google Home and noticed that only the Tapo doorbell camera was coming in under the Tapo app.  This made sense because I had never unlinked the Kasa app from Google home.  

So I decided to unlink both apps and then just link the Tapo app.  When I went to relink the Tapo app only the doorbell camera was available to add.  I speculated this was due to most of my devices being setup through the Kasa app.  So I took one device and hard reset it (Kasa plug) and added it directly to the Tapo app.  I unlinked and relinked the Tapo app with Google home.  Still, only the doorbell camera was showing up.

To get my Kasa devices to show up in Google Home I have to link the Kasa app to Google home.