What is the ruling on beliefs regarding the effect of using scissors, or calling out to someone who is going to do a good deed, or hitting with a wooden broom, or moving one's feet while sitting, or blue/black eyes, on causing disagreements, or spoiling work, or destroying things?

That which is not known to have benefit or harm, whether by religious text or by sensory experience, it is not permissible to believe in its benefit or harm, nor to believe people regarding it, nor to act upon their guidance. The scholars have explicitly stated that taking something as a means to an end, for which Allah has not given permission, neither religiously nor sensually, is minor polytheism (shirk asghar). In the hadith of Imran ibn Husayn, the Prophet, peace be upon him, commanded a man to remove a brass ring from his hand that was for Al-Wahina (a pain in the arm), saying: "Remove it, for it will only increase you in weakness, and if you were to die while it is on you, you would never succeed." And what you mentioned as examples, such as believing in bad luck when called from behind or before leaving, is from tatayyur (superstitious omens) and blameworthy pessimism in Islam, and it is an act of the people of Jahiliyyah (pre-Islamic ignorance). The Prophet, peace be upon him, forbade tatayyur and informed that it is a form of shirk.