Most Rhino 7 and Grasshopper plugins work in Rhino 8.
Plugins for Rhino and Grasshopper can be found on Food4Rhino
Note: Rhino 8 plugin support changes require updating some plugins to be fully compatible with Rhino 8. If you have a problem with a plugin, please report it here.
These Rhino 7 plugins have known Rhino 8 issues: