I kinda lost interest in Pokemon GO after they turned it into a bit of a grind when hunting shinys.
It's hard to think of a favourite because it's always changing. Squirtle was my favourite starter. Gyarados was always a bit of a holy grail pokemon for me. Hat Pichu makes me obsessed Mareep always made me smile in gen2. Larvitar is a close second because it's a cute little dinosaur, and tyranitar is like the Gyarados of Gen2 for me.
Torchic makes me squee in gen3 although I'm sad I missed out on party hat wurmple I call Ralts "sia" trapinch is also cute. cranidos is probably the last pokemon I have any real emotional attachement to, after that they don't mean much to me
I watched Pokemon on TV 17yrs ago when I hardly knew what was happening. The only thing I still remember is "Pikachu". I even got a Pikachu lunch box those days when I attend a birthday party. Long time ... I don't know anything else.