Typically my games have had a 2 sprite animation for blinking, with a blink sprite and a regular sprite only.
I'm currently working on a 4 sprite animation or a 3 sprite animation set, depending on what ultimately looks better.
This is a longer process to work on the sprites, but in the end I think the result is better. It makes the charcters feel more like they are actually there.
1st image is a 2 sprite animation style, typical to the game already.
2nd image is a 3 sprite aniamtion style, modelling that after games I know already
3rd image is a 4 sprite animation style based on a greaet new visual noverl game I saw recently
Currently I think I like the 4 sprite animation style the most.