The set of actions I use most is Paint the Moon's Essential Actions. It includes things like brightening or darkening a photo, lightening shadows, sharpening, fixing color (warming or cooling the image), repairing blown out areas, etc. I tend not to use artistic actions, but there are some beautiful ones out there. Paint the Moon and My Four Hens are the two action makers I've used, but they sell larger bundles rather than inexpensive, standalone actions you can try out. Here are links to the set of freebie actions each has on their site.
Paint the Moon:
https://paintthemoon.net/products/try-paint-the-moon/
My Four Hens:
http://myfourhensphotography.com/sho...lous-freebies/