Hello,
In Rhino 8.12 on Mac & Windows, not all packages show up in Package Manager… appears to stop somewhere around S (possibly the last S entry or maybe a fixed number?)
Found this post saying something similar that was fixed:
Perhaps something changed but it appears to no longer be fixed.
Is this repeatable on your end?
Thanks!
Hi Michael, thanks for reporting this. We’ll figure out the problem and fix it!
In the meantime, you can always use the search bar, if you know roughly what you’re looking for.
Thank you @will !
For sure, search seems to work just fine, thank you! Just reporting so the T and beyond plugin peeps aren’t left in the scroll bar dust 
RH-83850 is fixed in Rhino 8 Service Release 15