You need to start with what era you want: Pre war; 1060's and 70's; 80's; 90's modern. They all have a top ten
You also need to decide on bog standard; deluxe or custom as rifles from the 80's onwards come in all three formats.
Do you want field target rifles, target rifles or sporting rifles?
Buy John Walters The Airgun Book Fourth edition for most of the 80's stars and then Airgun and Airgunner for the later years.
Do you want one of the best from each maker or the best rifles from that era? For example HW 35E, 80, and 77 were better that anything British. Don't forget the Original 45 which was one of the best rifles ever.

Tell us which way you want to go. 22 rifles later and I still have holes in my 80's collection.