I'm very surprised you didn't mention XVG's exploited code, where a group of hackers exploited the mining protocol for 14 hours straight, mining 1 block per second (as opposed to 1 block for 30s). There are so many red flags for XVG but the penny value is attractive to the average Joe... their motto is "remember when Bitcoin was 1 cent".

Also on top of this XVG tried to patch the exploit with a hardfork but the code was so bad it desynced the wallet so now the coin is no mans land. Not sure if they've found a fix. I actually surprised this thing hasn't dumped to 50 sats yet.