Neutral tone and erhua (儿化) working as a word distinguisher
Are there any erhua-ed words that has a different meaning from the not "erhualess" word?


Yes, many, categorized as follows:


Nominalization (convert to noun), e.g. 盖 (to cover) -> 盖儿 (lid), 尖 (pointy) -> 尖儿 (tip)
Generalization, e.g. 眼 (eye) -> 眼儿 (hole), 
Derivation, e.g. 白面 (white flour) -> 白面儿 (drug)
Word simplification by replacing the last character with 儿, e.g. 把手 -> 把儿 (handle), which is different from 把 (to hold).
Changing tone, e.g. 脸蛋 (cheek, neutral tone) -> 脸蛋儿 (cheek, loving tone)



  Is there any list with these neutral/non-neutral and erhua/non-erhua (if they do exist) pairs?


Not aware of any. I am curious to see a comprehensive one, too.