The biggest names on the market are:
Al Harrington
Josh Howard
Brad Miller
Udonis Haslem
Luke Ridnour
Shaq O'Neal
Nate Robinson
Tracy McGrady
McGrady -- he is finished, he has lost his legs -- a terrible defender, weak rebounder and inefficient scorer. Does not help his teams, he hurts his teams.
Harrington -- A very poor defender and a very poor rebounder. A volume shooter who never passes the ball. Does more damage than good.
B.Miller -- a poor defender and rebounder and solid complementary offensive player -- preferably not a rotation player at this stage of his career but still useful.
Shaq -- a quality interior defender but vulnerable away from the rim, a very good rebounder, a very good interior scorer -- A horrible fit alongside Rondo. Not interested.
L.Ridnour -- coming off a career season, not sure if he can repeat his success of last season, but a quality backup point guard regardless -- looking for $12-16 million over four years, makes it difficult to sign him.
J.Howard -- a good defender capable of being a very good defender. A poor rebounder, lost a lot of his hustle plays. A self-involved offensive player, a black hole, an isolation based scorer who is inefficient nowadays. Even during his best days, he was only a mediocre scorer efficiency wise so the slightest decline in athleticism / shot creation / scoring ability was going to hit him hard. Looks like that happened. Highly injury prone, totally unreliable.
It's frightening that Nate Robinson is the second best player on that list.