Ironically, some of the biggest heartwarming moments come from Tedium, of all characters. In one episode, he gives a sick Kira a piggy-back ride after being an asshole to him the second they met each other.
Towards the end of the series, Tedium and Melody manage to have a civil and touching conversation, which ends with the couple hugging each other and saying how glad they were that they found each other again.
Episode Eighteen, "The Howl Through My Fangs". It is a Greyfus episode, and in it, Greyfus tends to a dying girl who wants to teach him origami (earlier she had created an origami of his ultimate form) and asks him why his ears are so big, why his arms are so large, and why his snout is so long. In the climax, Greyfus tells her that the reason all of those things are is that he can always hear her cries, run towards her if she needs help, and howl for her proudly. She eventually dies, but then we see her ghost saying thank you. D'awwwwwwwwwwwwww!