A whole lot of those old Motion 4 templates were ... ahem... junk. If you check the Motion menu, you should see a Download Additional Content link... The *best* of those old templates have been updated for Motion 5. Among those will be Atmospheric, Decode, Pulse, Skyline, Snap, Splash, Swarm and Vine. I believe Atom Strand and Rotation HD are in there too under the 3D Text category, and once installed, they will be accessible from the Open dialog from the left column under Compositions.
Since you had Motion 4, installing Motion 5 did not remove those old templates — you still have them. You can find them here:
Macintosh HD/Library/Application Support/Final Cut Studio/Motion/Templates/
They will all open in Motion 5. However, there are some filters and generators (and miscellaneous other things) that have been deprecated and removed over the years, so not everything may work as it should. Examples would be Primatte RT, Droste, etc... all of the LiveFonts are gone though and all you can do is quietly (and briefly) morn their passing and move on. They won't be coming back.
HTH