Apply CSS to a group of css classes containing col- substring

You could use [class*="col-"] CSS attribute selector to select any element contains at least one occurrence of col- as its class value.

[class*="col-"] {
    border-color: red;
}

If all values of class attributes begin with col-, you could use [class^="col-"] selector.

However, in order to prevent for classes like foo-col-1 to be selected, you could use a combination of two above selectors as follows (Thanks to @JosephSpens):

[class^="col-"], [class*=" col-"] {
  border-color: red;
}

WORKING DEMO.