Platies and mollies! They always nibble my finger when I open the cover. They're so friendly (apart from the odd nasty one). Never kept guppies, myself.
I have mollies, platies and guppies and they are all peaceful and friendly. I think they are a bit thick. I had a dog like that and she was lovely but dim. She didn't learn to sit until she was 10 !
its Endlers, guppies, mollies and platies for me they are great and friendly, they all love eating out of my hand , they all go crazy when i put my hand in the tank and they play around my fingures and go in circles.
I have one bully molly ( dalmation but with a blueish reflection) who hates one of my fancy guppy males and a baloon molly he keeps hitting just those two guys, so i ended up putting him in a separate tank alone, i do love his colors thats why i didnt return him to the LSF