We are a software development company with only 8 employees but all of us are seniors in different fields. We have developed 2 products from scratch for a big international company with over 35k employee (6-12 months developments). One of them is an app which is mandatory to use for all of the 35k employees. We passed all request from integration with Active Directory, SAP, GDPR, Russian legislation, Penetration tests and a lot of paperwork which are highly demanded if you are working with an international company.
That's great news about your success so far. I've done enterprise business development for enterprise technology, workflow reengineering, and strategy projects. I've also been on the buying side (part of a $110 million IT budget for a name brand Wall Street firm.)
Given that you have 8 people, I will assume you have to be very focused with your business development time and money. My quick reaction (unencumbered with too much information) is that you should focus on getting warm introductions, direct conversations, and face-to-face meetings. This will take some strategic networking. Sources of network include your team's own relationships, referrals from your happy clients, and any meetings of similar client companies. One piece of marketing collateral worth producing is a one-page case study, highlighting your project, preferably using your client's name. (If you can't get permission, just describe them in general terms.) You can use the piece to focus your story and share with prospects.
That's all I can think of without more context. Set up a call, and I can help you think through business development strategies from the sell side and the buy side.