Here is some software I use on my MacBook Pro and recommend.  I have no commercial interests in any of them.

BBEdit (or it’s free cousin TextWrangler)

Available from Bare Bones Software or through the App Store.  TextWrangler (a free “lite” version from the makers of BBEdit) probably fulfils my requirements but once I had the funds I purchased the full version.  The best text editor I have used on any platform.  I have been using this product since the days of Mac OS 7.1 on a PowerBook 150 (when BBEdit Lite was available as opposed to TextWrangler).

VLC

A media player available from VideoLAN.  Plays just about any format I need.

PCalc

Simply the best calculator application out there (and available for iOS too).  I used to use the “lite” version of PCalc on the aforementioned PowerBook 150 during my university engineering studies.  Well worth the money.

VirtualBox

A free virtualisation platform (now available through Oracle).  Worth a look if you need to run old software on old operating systems every now and then.