There are so many excellent tools for different purposes that I think I need to start with two pieces of rather generic advice.
Firstly, your time is expensive and limited; so fast, easy things are generally better value than less slick free ones. Secondly, where a product has a free version and a paid-for version, the latter is almost always a lot better. Insisting on “free” is normally a false economy.
Here are my five favourites.