I lost my last phone how do I get my old pictures vids back

If your iPhone was syncing and backing up to iCloud, then all your data should be available at iCloud.com.

As for your pictures and videos, you would need to have set up iCloud Photos before you lost your iPhone. Otherwise they are only on your lost iPhone and nowhere else. In that case, you cannot retrieve them unless you find the device.

See Set up and use iCloud Photos - Apple Support