Despite many other options being available, I still use Vim daily for various tasks from taking notes to writing this post. However, I'll admit that Vim has a lot of strange and somewhat arbitrary key combinations which are quite useful. I'm going to list a few which I use daily which might not be common knowledge or I frequently forget.

Mode	Keystrokes	Effect
Normal	$	Moves the cursor to the end of the current line
Normal	0	Moves the cursor to the first non-whitespace character of the current line
Normal	shift+j	Joins the current line with the line below it
Normal	~	Toggles between capital and lowercase letters under the cursor
Normal	]s	Moves to the next misspelled word
Normal	[s	Moves to the previous misspelled word
Insert	ctrl+x s	Brings up a list of suggestions if a misspelled word is after the cursor. The list can be navagiated with ctrl+n and ctrl+p
Normal	ctrl+a	If the cursor is over a number, increments it by 1
Normal	ctrl+x	If the cursor is over a number, decrements it by 1
Normal	z=	If set spell and the cursor is over a misspelled word, will bring up a list of correcton candidates
Normal	shift+h	Moves the cursor to the top of the screen
Visual Block	shift+I	Enters insert mode and inserts whatever is typed in each highlighted square