LogFAQs > #979830111

1. Red Ribbon Army takes over for a while (probably, unless some of the other strong dudes steps up in Goku's place)
2. Gero is maybe still a mad scientist hanging around but probably his androids won't be as strong this time without as much strong people data to collect
3. Someone like Pilaf who's searching for the dragon balls maybe possibly actually assembles them and becomes immortal
4. Eventually Raditz comes. But if Goku's already dead not sure if he bothers destroying the planet or not
5. Elsewhere in space Frieza becomes immortal with Namek's dragon balls and takes over the galaxy, even more than he already did
6. Majin Buu is eventually resurrected, if Earth is even still around. Supreme Kai almost certainly can't stop him on his own. Earth and presumably the entire universe is then taken over by Babidi and Buu unless Immortal Frieza can do anything about that

I'm super hazy on pre-Z dragonball story so not sure, but that's my random guessing