I recommend:
Koe Koi, if you want something cute and innocent
Love That Makes You Cry (no it's not tragedy), but it's not really heart fluttering romance more like heart soothing one
Soratobu Kouhoushitsu
Bijo to Danshi
Haven't watched these but you might want to check:
Hapimari
Please Love The Useless Me
Toki wo Kakeru Shoujo
Sumika Sumire
Okitegami Kyoko no Biboroku
Second Love
