Hi there. There are 3 different types of dragonballs, quest, regular and pvp.
Quest Dragonballs
At the beginning of your questline, you will receive 7 quest dragonball which you get from rewards. They look like a nonshiny small dragonball at your inventory.
Regular Dragonballs
This ones can only be found by drop from dragonballmobs (you can see them with dragonball radar chip equiped in your scouter).
PvP Dragonballs (Scramble)
Can only be found at channel 1. You have to enter scramble mode to see them on the world map. Beware if you take one, you can be attack at any time. They look like a black orb if you see it on the ground.
No picture available
Greetings
BBQ