Open the Contacts app
Tap Lists or Groups if available
Check the most recently created contact at the top if sorted by date in a third-party contacts app
Open the Phone app
Tap Contacts
Review recent entries manually
Open the Messages app
Check recent conversations for new contact names
Open the Phone app
Tap Recents
Tap the info icon next to a number to see if it can be added to Contacts
Use Siri and ask to show a contact if you know the name
Check iCloud Contacts on a browser if your contacts are synced
Use a third-party contacts manager app with sorting by creation date or last updated date