Hello watchman19,
Thanks for using Apple Support Communities!
We understand you are experiencing an issue when using Migration Assistant to move your data from your old Mac to your new Mac. We are happy to help provide some guidance.
If any of your data did not move over after using the Migration Assistant, let's check to see if any of that data might be stored in iCloud and needs to be synced from there. Take a look at these helpful articles to make sure your device is logged in to your Apple ID and synced with iCloud:
Access your music library on all your devices
Set up and use iCloud Photos
If needed, you can also move your files manually. Take a look at the places your data is stored and how to move it:
OS X: Manually migrating data from another Mac
We hope this helps.
Best Regards.