Do you have a favorite stationery product?

Erasable pens have been popular in Japan these days, and I've used them frequently at work and study.

However, I really like normal pens because they looks various different and artistic.

I've often used pencils as well for oil painting, but they look the same and too simplistic for my taste.

However, I really like normal pens because they looks various diverse and artistic.

Careful using "various." Although it is an adjective, it's one of those words that isn't usually left on its own. Its more natural to have it used with a noun directly, for example:

"I read various books." (correct)✅

"I read books that are various." (unnatural)❌

In this context, I think "diverse" is a better word to use :)

I've often used pencil as well for oil painting, but they look sameplain and simple.

"Same" follows a similar sort of nuance I mentioned above.

I think "plain" is the word you're looking for :)

Erasable pens have beenare popular in Japan these days, and I've used them frequently at work and during study.

Alternative: Erasable pens have become popular in Japan recently,

However, I (really like / prefer) normal pens because they lookshave various andstyles and are more artistic.

It sounds like you like normal pens more than erasable pens - if so, you should use "prefer"

I've often used pencils as well for oil painting, but they look same and simplare simple and look the same.

More natural

Erasable pens have been popular in Japan these days, and I've used them frequently at work and while studying.

However I really like normal pens because they looksre are various andtypes and they look artistic.

I've often used pencil as well for oil painting, but they look the same and simple.