In that category; my ,s
and ,S
both pre-fill the ex command with :%s///
, but the former places the cursor in the search pattern, and the later in the replacement.
nnoremap ,s :%s///<left><left>
vnoremap ,s :s///<left><left>
nnoremap ,S :%s///<left>
vnoremap ,S :s///<left>