u/lkc159

Hint 1: >!One nod is good. Two nods, very good. There's only been one actual smile on record...!<

Hint 2a: >!It's from a movie...!<

Hint 2b: >!That had a sequel released this year.!<

Answer in comments!

Kind of a "you probably won't get it if you don't know it", but I don't think it's that niche and I'm pretty sure most people will have heard of it before in some form. Not my favourite kind of sequence tbh - I prefer ones that you can logic out and/or have an epiphany about - but this thing was stuck in my head for the longest time, so why not.

Hint 1: >!The green heart is jealous and the red eyes are crying.!<

Hint 2: >!Victoria would probably make you sing.!<

Hint 3: >!The original version of the song is in French and placed 4th at Eurovision in the 60's.!<

Hint 4: >!It's a sad love song.!<

Answer in comments.

Here's one that's pretty simple in concept, though maybe a little tricky in presentation. Not sure if it's been done before; quite surprised to not find it (maybe I'm just bad at searching?)

Hint 1: >!Not the periodic table!<

Hint 2: >!One more clue in either direction would give the game away completely!<

Hint 3: >!This sequence is infinite in either direction!<

Answer in comments.