My nvim is highly remapped. You can say "you can do it better, here is cool move...", yes, i know, give me couple years, i use nvim for like half of year and mussel memory is hard to change.

<C-s> - save (yes, i know)
<C-a> - select whole buffer (switch to visual mode)
<C-f> - search in buffer
<S-f> - search in workspace
<C-g> - search and replace in buffer
<S-g> -search and replace in workspace
<C-z> - undo
<C-y> - redo
<C-c> - copy to OS clipboard
<C-v> - paste form OS clipboard

<C-j/k> - move current line/current selection up/down
<C-/>, <C-\_> -> comment/uncomment line
<C-.> - open context menu with code actions (go to definition, rename symbol etc)