The first site of this kind was IMBD, which was created in the 1990s, and was one of the first websites I ever visited. It solved the age-old annoyance of the ‘who is that actor and what is that movie he was in’?
The Shazam app is probably my most-used app. When I hear music in a shop, I often Shazam it because I like the song or because I have heard it before and can’t remember the artist.
Plantsnap allows you to identify plants, which is probably what I need as I am awful at it.
Google Lens and ASOS allows you to search for fashion items via photographs. There are also apps to identify stars.
Any others I should know about?