@futurebird I meet different groups of 30-60 people once a year at conferences. If they send round a group photo afterwards, I try to make notes and match names/conversations to faces. It sometimes works. If not, I'm fine with asking for a reminder (preferably not more than once per meeting...)

At more "business networking" events, I sometimes ask if I can take a photo of a new-to-me acquaintance with their name badge ‍️