Involvement between the dead and sheidim/Spirits: R. Chagigah 3b "SheTishreh"
Spirits of the dead affecting the living: Berachot 18b; Shabbat 149b, 152b [2x]
Whether the dead sense their own decay: Berachot 18b; Shabbat 152a
Whether the dead sense what is happening in their cemeteries: Berachot 18a
Whether the dead know who is going to die: Berachot 18b
The dead present at their Eulogy: Shabbat 153a
Rav Nachman appearing to Rava after death: Moed Katan 28a
Rava appearing to his brother, Rav Seorim, after death: Moed Katan 28a
Rabbi Chiyya and Rabbi Yonatan walking in a cemetery, and their dialogue on the awareness of the dead: Berachot 18a-b
A pious man who eavesdropped on conversations between deceased spirits about the year's upcoming weather: Berachot 18b
Zeiri speaking to his deceased hostess, to find out where his money was stored. She asked him to have her mother send her cosmetics with a certain woman who was to die the next day: Berachot 18b
Ov and Yidoni
[Im-]Permissibility of using a Medium [Ov]: Pesachim 113b [See Rashi, Rashbam "Kaldiyyim"]
What an Ov does: Rashi Keritot 3b "Hoil v'ein bo maaseh"