Os Anões usaram seus Anéis para estabelecer seus tesouros (que por sua vez atraíram dragões). Conforme Wiki : " Gandalf menciona um boato de que as sete hordas dos anões começaram cada uma com um único anel de ouro ".
Em termos de efeitos: de acordo com LOTR Wiki :
Sauron, according to portions of the Silmarillion, was unable to force the Dwarven bearers to submit to his will. Indeed, the rings did not even turn them invisible; they were immune to some of the more detrimental of the rings' effects.
It is believed that the dwarves' natural hardiness, and the fact that it was only the more powerful dwarf lords who possessed them, made them resistant to Sauron's control.
The net effect of these rings was to bring vast wealth to the wearer and cause him to become extremely greedy.
At the time of The Lord of the Rings four rings had been consumed by dragon fire and the rest acquired by Sauron. The mightiest of the Seven was taken from Thráin II, heir of Durin, who had been captured, imprisoned, and tormented by the Necromancer (Sauron in disguise) in TA 2845.
A Man who gained possession of one of the Seven likely would have become a wraith, just as those who wore the Nine did.