Have there been any friendly alliances, negotiations or agreements between Iran and Israel after the Iranian revolution, especially during the Iran-Iraq War? Or even some kind of help from any of the countries to the other?
Yes. The main Wikipedia article for this is the one on Iran–Israel relations.
Among others it mentions Israel's role in the Iran–Iraq war: Israel sold weapons to Iran.
Israel's relationship to Iran seems to have been a pragmatic one: The enemy of my enemy (Iraq) is my friend. That changed in the 1990s after the defeat of Hussein's Iraq and the rising fear of an Iranian nuclear program.