Anybody know of a jobs boards for those wanting to earn some income using LibreOffice?
I tried to find job offers on Upwork a long time ago. Job offers are extremely rare, working conditions are not very loyal to freelancers, competition among contractors is extremely high - it is difficult to get a job. This is understandable - usually people who get an office for free are not ready to pay extra for anything, they expect further free support. And the attitude of the exchange to freelancers is also understandable - they are paid not by contractors, but by customers.
Therefore, my answer is no, you are unlikely to get a job through job boards, only through personal connections, through acquaintances.