Tank size will dictate everything here, but if you want to stay away from the typical CUC of snails and hermits then consider an Urchin for algae duty. IMO you will find no other equal in terms of algae duty. A tuxedo will take care of most algae and a longspine will take care of all of it, including the problematic ones. Stay away from the sand sifting stars, they will just die. Serpents and brittle stars are both good and will grab and missed food and such but will do very little to sift the sand. better bet is a goby for that duty, or a conch will be just as good. As far as pest duty not all wrasses are created equal. As they get bigger they will perform less coral pest cleaning duty as they just cant get to them. My favorites are in the Pseudocheilinus family. these include the sixline and mystery but they may get aggressive as they get older, but don't require sand. Also the Halichoeres family like the melunarus. but when bigger they seem to stop cleaning. They seem more on the mild side, but do require sand. I've found all other wrasses to be useless as far as pests go.