All animals melt my heart but especially baby ones, the cuteness, and the way animals treat each other, the way one species can take care of another species.

An amazing kiss can melt me into a pile of moosh.

People being reunited with people, people being reunited with animals (those youtube videos can really make me cry)

Puppies.

The random squeal of delight that a very small child makes that just rings through an open public space. A couple walking together, holding hands, and occasionally stealing glances that radiate affection. My cat, Hitch, when he greets me at the door wanting up on my shoulders and how when I sit down he crawls up on my chest and boops me on the chin. The end of "The Iron Giant"... No following. When my kids voluntarily share something that's very important to them.

puppies

Babies! All kinds, human and otherwise! Awwwww....

Animals being rehabilitated and/or saved.

Parent & child reunions.

memories of my grandmother's hands, the smell of baking cookies, old dogs sleeping,

Dogs of any kind...Dogs will give you their purest, most honest devotion, and do it without being judgmental. Whenever I'm having a bad day, I go to the local Humane Society and visit the dogs (it usually helps)

A good song, particularly a cool guitar lick or pretty vocal harmony.

Animals for me too-puppies and kittens I'm absolutely gaga.
Compassion and kindness stories from people in need and who helped them.

I never thought I would get attached to a puppy again, then carame along my grandkids 5.5 lb puppy.
Lol

Babies. And elderly couples who still love each other. I feel like animals are a given, too.

Love and kindness penetrates my heart.

The surface temperature of the planet Venus!

Peter Paul Rubens paintings.

Rachmaninoff

Puppies and kittens.

Kindness when offered between complete strangers.

A deep, passionate kiss. The kind where you just have to put your hand on her cheek to be sure it's real.

Purple and orange sunrises on the mountain where you can see the mist like clouds among the trees below.

Pale, moonlit nights with a crackling fire and the right person to share it with.

Hearing someone say "I love you."

"Restoring faith in humanity" videos om YouTube. Getting choked up just thinking about it.

Dogs!

1400 to 1800 fahrenheit....wah wah wahhhhhh....my cat 'cutes' me all the time...people helping people...

When a slow sun rises to warm the day. Painful brilliance that makes you avert your eyes...and drives away the darkness.

I have no heart my ex wife ripped it out and stomped a stiletto heel thru it.

My granddaughter ... And she knows it !

Young puppies and kittens. Seeing couples looking at each other and smiling, obviously in love and so happy to be with each other. Hearing the laughter of a friend you're cheering up. Listening to "That I Would Be Good" by Alanis Morissette, or "The Rose" by Bette Midler.

Children (as long as they belong to someone else). The smile of a baby. A good song. Coffee. A good story.

Haha, my first thoughts were similar things (I didn't even read your question in full until I thought about it myself): when love or kindness is being expressed and felt; kittens and puppies (for me kittens first , music, and a big heart always melts my own heart And by the way I don't identify my heart as heathen as I've never really lived in a religious environment and the word is not in my vocabulary