Cafe is a terrific artist resource for calls of entry. I have been with that site many years and most of the entries are free. Also, it has many public art opportunities that are supported with grants and percent for art projects nationwide. The calls can be national, regional or local. Also you can change the list so it shows days to deadline. I have had my work in a number of national juried shows thanks to CAFE.
Also, many states have a public site dedicated to art promotion. In New York a good resource is NYFA.
Here are others I have used and recommend:
http://www.artshow.com/juriedshows/
http://blog.re-title.com/opportunities/
http://rhizome.org/announce/
https://filmfreeway.com/