A recently updated support document confirms that starting with iOS16, the "FindMy" project limit has been increased from 16 to 32 items. It's very easy to accumulate AirTags and "FindMy" compatible devices, so for some power users, Apple's previous limit of 16 may soon be reached. However, starting with iOS16, this limit has increased, but Apple has not mentioned it until now.
Starting with iOS 16, the Find My Items limit increases to 32, according to a support document shared by X user @nicolas09F9 and first spotted by MacRumors. That's double the original limit of 16, which includes AirTags, FindMy-compatible trackers and AirPods.
Information from supporting documentation:
You can add up to 32 items to Find My. In addition to AirTags and third-party FindMy network accessories in the Items tab, AirPods Max count as one item, AirPods and AirPods Pro (1st generation) count as two items, and AirPods Pro (2nd generation) count as three items.
While 16 devices sounds like a lot, it's not hard to hit that number, especially since the AirPods Pro 2 take up three items at a time. But reaching the 32-piece limit seems impossible for ordinary users in a short time.