Games that still work online

[JosJuice]

If the servers are still online, you can play on them, but you'll need to import the NAND of a real console in order to get a valid identity (Dolphin's default identity has been banned due to abuse), and you'll also need to extract certificate files from the NAND. (If you're using a recent development version of Dolphin, Tools > Import BootMii NAND Backup will automatically extract the certificate files for you after importing the NAND. If you've already imported the NAND, you can use Tools > Extract Certificates from NAND.)