What is a word or good phrase for when you like someone, but there are no specific attributes you like about them? The reason you like them is just unknown.
English has lots of words, but it doesn't have words for everything. You should either tell us what the precise word or phrase is in your native language, or explain why you think English would have a word for this concept.– James KMar 21, 2018 at 19:40
I just like you/him/her/etc.
You can say this when you don't know exactly why you like the person, or when you're deliberately hiding the reason in order to be flirty.
"There is something about [X]" is a useful phrase, although it can have positive and negative connotations (i.e. it is neutral):
There is something about Mary that makes me like her.
There is something about Freddie that makes my skin crawl.
The default connotation probably depends on context:
I think generally you would say that you are attracted to them:
I can't explain why, but I'm attracted to this woman!
There are probably many, but I would recommend:
I have no idea why I like her.