We found a site site with 246 installed WordPress plugins.

It’s the highest I’ve seen, but surely this is not actually a record. What the most installed plugins you’ve seen?

I’m not sharing the list of plugins as that would not be very privacy friendly, but about 25% were active. And a lot of plugins are add-ons to @BuddyPress, @WooCommerce, The Events Calendar, @elemntor and @LearnDashLMS.