And, before that, Howard's attempt to comfort Vince when he says he 'doesn't want to die'.
Old Gregg ending up in Howard's wheelbarrow at the end of the live show.
Vince giving his really nice cape to a homeless man in a (somewhat convoluted) attempt to show Howard how much he values their friendship.
In the same episode, Howard being accepted by the bin men. In the past, Howard has claimed to be friends with certain people and groups, only for them to outright state their hatred for him. Not so with the bin men. It's clear that they all respect him and think of him as a friend.
Okay, it may only have been done to save Vince's life, but Vince and Howard's kiss at the end of 'Party' definitely counts as this for some fans.
Basically every Friendship Moment between Howard and Vince, when we see that under all the egotism and sociopathy that they do really love each other, and value their friendship above all else.
In a case of Fridge Heartwarming, the scene in The Power of the Crimp where Lance Dior (Who is copying Vince) tries to seduce Howard away from Vince. After Howard is tempted, Vince comes out angry and asks him how he could even consider going with Lance. Howard replies that he's paranoid and dark, and Lance has a sunshiney happy feel to him, and "together we make one whole person". This only made Vince angrier, saying "That's our angle!" At first you just think this is funny, but then you realize Howard and Vince basically just called each other their other half because they feel like an incomplete person without the other.
Vince giving Howard a poncho and the two dancing together at the end of "Charlie".