Good reasons for being banned? I know developers who have been banned for
1) Reselling their pixel devices (https://www.theguardian.com/technology/2016/nov/17/google-su...)
2) Using paypal and not Google wallet (when it launched)
3) App being too similar to other popular apps
4) Related account that has a ban using multi-sign (This thread)
5) Invalid traffic to adsense
6) For expired credit cards or invalid charges in Google wallet
7) For bank account switching problems even if there is no fraud (https://www.reddit.com/r/google/comments/3ki65d/warning_to_a...)
8) For attempts to avoid buying apps or too many refund requests (https://www.reddit.com/r/tifu/comments/8kvias/tifu_by_gettin...)
Some unlucky people had all their google accounts purged including Drive and Gmail (Especially with monetary issues like invalid adsense clicks, invalid charge on wallet, too many app refunds)
Keep in mind that the ban is LIFETIME and any account that you multi-sign at any point in your LIFE will also be banned AND there is zero customer support. Some users have been banned for multisign issues even after 8-10 years.