You can filter this list to see 200+ GDPR fines assigned to sole proprietors, the smallest of small businesses, individuals that haven't even registered a separate entity for their business:
https://www.enforcementtracker.com/
They're only cataloging the (2500+) publicly known ones, most of which have a link to a news article. As an example: some guy in Croatia emailed a couple websites he thought might be interested in his marketing services, and provided a working opt-out link in his cold emails. One of them reported the email to the Italian Data Protection Authority who then put him through an international investigation and fined him 5000 euro.
"Assuming here that the reasons expressed in the aforementioned document have been fully recalled, [individual] was charged with violating articles 5, par. 1, letter a), 6, par. 1, letter a) of the Regulation and art. 130 of the Code, since the sending of promotional communications via e-mail was found to have been carried out without the consent of the interested parties. Therefore, it is believed that - based on the set of elements indicated above - the administrative sanction of payment of a sum of €5,000.00 (five thousand) equal to 0.025% of the maximum statutory sanction of €20 million should be applied."
