buttigieg should expect to be competitive in most states:, 
Arkansas, California, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Utah, Vermont, and Virginia

biden should expect to be competetive in far fewer states:
Alabama, Arkansas, North Carolina, Oklahoma, Tennessee, Texas, and Virginia

klobuchar has a few shots, too:
Maine, Massachusetts, Minnesota, Vermont

i don't think warren should expect to be competitive in any of these states, although she may win delegates in a few.

only sanders can expect to compete everywhere, except for the black-dominated alabama:
Arkansas, California, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Texas, Utah, Vermont, and Virginia 

and, bloomberg? we don't know. i don't expect him to do well, though.