Hi sir, it seems that you want to detect data (pet names) related to other data in some column or table (Names), and this data you detected you want to show it up in a drop-down list, so okay we can do that easily by two ways depending on a question.
Do you want detected data results when you select the cell or name in a pre-listed list? or you want the data when you type the name you want in a specific cell?
If you want to type in a cell the name you want to detect pets of it we can use simple excel functions like match and unique in somehow together, and if you want to present the data of name (pets) when you just select the cell of a name we use a VBA code with subroutines to do this automatically and both solutions can be easily copied to any sheet you want and work effectively.
I am trying to find solutions based on what you draw, I don't see any samples of work.
I will be very happy if you contacted me to work together, waiting for you, thank you.