Sabriel

Sabriel is a relationship between Sam Winchester and Gabriel.

Fanon
Sabriel originally started as Sam/Trickster. The reason people ship sabriel comparison to destiel, so both Winchesters have angels.

In Tall Tales, the two immiediately hit it off. Both Sam and Gabriel were obviously flirting.

The reason people do not like sabriel is because in "Mystery Spot," Gabriel killed Dean a million times, but this gave sabriel shippers an amazing line, "It appears Sam has hit Gabriel's mystery spot."

In Hammer Of "The gods," it is seen that Sam is upset because Kali is on his lap. When going against his brother, Lucifer, Gabriel looked back at Sam.

In the episode after "Hammer Of The gods", "The Devil You Know," Sam screams at Crowley saying, "We lost people on that suicide mission, good people!"