Do anyone know a website for Classic Mode trading?

Do anyone know a website for Classic Mode trading?

It can be done here if the filters are set correctly and I do recall seeing a few members here who have their profiles marked Non Expansion as well.

Here you can find non-expansion tag but there this no item listed.
There are some classic players but way less than expansion.

For Non-Expansion (Classic) D2R trading you can use the marketplace here at diablo2.io, just select the 'Non-Expansion' filter when making or looking for listings. As others have pointed out its a pretty small number of players and will be tough to find people to trade with, especially on a smaller marketplace like this You might actually have more luck on Traderie or D2JSP.