It would be best to only have as many as you actually need. Too many plugins increase the odds of a security vulnerability on your site that bad actors could exploit. Too many plugins can also slow down your website considerably. Pay attention to multi-purpose (or all-in-one) plugins that do multiple things. If you only use one of its features, find a smaller plugin that does just that one job. It would be best to keep your plugin count under ~20 plugins for your WordPress site. Also, consider using only the best plugins with reliable code and frequent updates.