Both personally and professionally, the male dyad fascinates me. My recent failed attempt certainly provides motivation for research; I am a Five after all and take comfort, real or illusory, in information.
But I watch and consider all kinds of men who are two-by-two. I just did a quick survey in my head of varieties of iconic "buddies" (a word known in English only since 1850; probably a form of "brother"), mythical, historical, fictional, in literature and in popular culture. I looked for two guys who formed a strong bond which was the dominant bond in their lives or in the story, who are not usually related by birth and who are not overtly sexually involved. The immediate commonalities kinda leap out, but the variations and pecularities are just as fascinating.
Gilgamesh and Enkidu, David and Jonathan, Jesus and Peter, Jesus and John, Sergius and Bacchus, Gautama and Ananda. Achilles and Patroclus.
Cisco Kid and Gordito/Pancho. The Lone Ranger and Tonto. Marshall Dillon and Chester. Boss and Charlie (in the terrific Western Open Range). Seth and Sol (in Deadwood). Starsky and Hutch.
Batman and Robin. Kirk and Spock. Jack and Daniel (in Stargate SG-1). Tod and Buzz (Route 66). Jim and Blair (TV show The Sentinel) . Sam and Dean (brothers by birth) in TV show Supernatural.
Captain Jack Harkness and Ianto Jones (in Torchwood)...one of the few whose connection is also erotic.
Holmes and Watson. House and Wilson.
Laurel & Hardy. Martin & Lewis. Abbot & Costello.