These conferences provide you very good opportunity to meet good scholars from everywhere around the world. If you did so, you can ask any of them to co-operate with you and to help you publish your paper in good outlets.
You can find many researchers in the same field of your studies by searching on each research topic of you in Research Gate site, then you can select persons you feel that they have the same research interests and see their pages to see their skills and research contributions. Once you find suitable researchers you can invite them for co-researching by sending messages to them via research gate or their E-mails that can be found on any published papers by them.
How to find an international co-author for my research or any other research?
Beside ResearchGate, you can also search from Academia, Mendeley, various journal articles etc. as well as from Google Scholar / Internet. Networking through research conferences, checking with your peers, words of mouth can also help. By the way, based on your research & literature review in your manuscript, you should have some ideas who are the possible scholars you want to co-author with. Wishing you all the best.
You could perhaps pose a question on ResearchGate asking for co-authorship but you need to specify the related topic and details of the research. In this vein, interested colleagues may reach out to you.
I think attending international conferences is a major avenue for collaboration/ co-authorship. Alternatively, you can search for researchers in your area of interest requesting for collaboration.