the threshold for what's considered a jobro varies from person to person (i.e. someone might think mamezuku is the jobro and not yasuho) but i'll just say in this context that a jobro is the character that i first think of when it comes to their relationship with the main jojo of each part. so:

• gyro zeppeli
• yasuho hirose
• dragona joestar
• bruno bucciarati
• ermes costello
• okuyasu nijimura
• noriaki kakyoin
• caesar zeppeli
• will zeppeli

now if we shift the threshold from "jobro" to "jobro groups" then my ranking changes somewhat

• team bucciarati
• morioh gang (part 4)
• joe kid and iulius caesar zeppeli (feat. mountain tim and wekapipo)
• green dolphin street crew
• team jodio
• morioh gang (part 8)
• joestar group
• joseph's allies
• jonathan's allies