^^ Yeah I'm glad he stopped that too.
So I couldn't find the gifset but I did find this Bellarke related one if that helps. Also it's pretty and Bellamy's smiles are always welcome.
x
(one of the gif wasn't working but anyway we can't really see the smile in the one missing so...)
From memory:
Season 1:
1X01 : Bellamy smiles watching Octavia stepping on earth
1x02 : Does the annoying "Brave princess" smirk count ? Does smirk count in general ?
1x03: he smiles at Charlotte after making a joke about her having to carry a tree.
1x06 : His sister's keeper, Bellamy smiles at Octavia more than once in the flashbacks.
Then I think that he kinda smirk to Raven saying something like "see you are a pain in the ass but we need you", I don't really remember.
Pretty sure he smiled at O when telling her that his life actually started when she was born.
+ the apple one:
Season 2 :
He smiles in Clarke's shoulder during the hug in 2x05 (that the gif missing), does he smile at Octavia too when he sees her ?
Honestly I don't recall many smiles during season 2...
Season 3: 3x01, the rover delinquents scene. Is there any more smile ? Yeah season 3 is all about angst.
Season 4:
4x05: when he find out that Octavia survived
4x08: when he takes a drink/whatever the hell you want from Jasper
4x12: Smiles at Clarke before crashing the trunk
4x13: Smile when O tells him she loves him + "cold sweat" + I think he snort/smile when Clarke tells him she didn't like him at first.
And that is all I can remember.