I want to suggest the implementation of common keyboard shortcuts in MS Excel to OnlyOffice, a big slow down for my case is the lack of CTRL+D shortcut - fill down.
As others have suggested, user defined keyboards shortcuts will be more than welcomed but, in my humble opinion, if the majority of MS Excel shortcuts are implemented, it will make a lot of people happy.
We have created a suggestion to add this shortcut. We will consider adding it in the future. I can’t share the timeframe yet. However, we will post an update here as soon as it is implemented.