Welcome to the community forums.This community forums is a very good platform to ask the questions and try to help others.
Coming back to your question !!
Yes marketplace have so many magento 1 - one step checkout extension , few of are also support B2B functionality which works on B2B functionality as well.
Refer this link for the same - https://marketplace.magento.com/catalogsearch/result/?q=one%20step%20checkout
Hope it helps !