i got to take a nice little dive through e621 thanks to this ask so thank you~
it's impossible for me to pick favorites, but those that i'd dare put at the top of the list (in no particular order) would be: Orf's Sam and Eddie, Sylvanedadeer's Sylvane and Kamos, Videah and his dad James, Sobek's Lorenzo and Oliver, Smallsrabbit's old donkey boys, Delirost's Deli and Vic, Unpopularwolf's Cliff and Elliot, Zourik's Incineroar family, Snoopjay's Seth and Lucas, Aejann's RJ and Keith, and Quasarbearcat's Regulus and Orion...would you believe this is already narrowed down? i'd be here forever if i listed down every dad-son pair i loved!