#1 Tommaso Ciampa and Johnny Gargano
Johnny Gargano and Tommaso Ciampa were once part of DIY, former NXT Tag Team Champions and were the best of friends. The duo were so close that they once lived together and Ciampa was even part of Gargano's wedding when he married Candice LeRae back in 2016.
Of course, this was all turned on its head back in 2017 when the two Superstars were unable to reclaim their championships in Chicago and so The Psycho Killer decided that it was time to end his union with Gargano.
This later lead to Gargano and Ciampa having a back and forth rivalry which has lasted over the past three years, with the two switching roles recently with Gargano becoming the heel in the feud and preventing Ciampa from winning Goldie back.
Even though the two Superstars are sticking to kayfabe and have stopped uploading images of them together on Instagram, they are still very good friends and still spend a lot of time together out of the ring. Their chemistry both inside and outside of the ring is the reason why this is one of the best WWE feuds in recent memory.