I did some experimentation on some low level coop dungeons (costs basically no stamina)
Machine Zeus pairs best with other unconditional leaders (duh). He also pairs well with light row leads (also huge shocker).
Some of the more unusual but successful pairings for low level or alt technical farming (do pys invade coop?)
Xmas Ars Paulina with a blue/red team sans Mech Zeus. The team my alt used was Paulina, Scheat, Urd, Alrescha (I didn't have another B/R to test that wasn't a dupe and the SBR is huge), Mori
I used Machine Zeus, Xmas Paulina, Urd, Mori, Scheat.
This combination did a shitload of damage with a single blue TPA. Urd was mostly used as a heal. Binds are occasionally a problem if Zeus doesn't have hearts to work with but a little research and you can pop Urd before that happens.
The Machine gods 1 pantheon is also a solid pairing if you have the machines to run it.
Alt used Antares, Alrescha, Scheat, Urd, Mori
I used M. Zeus, Scheat, Australis, Spica, Urd, again urd is for healing since Scheat does 99% of the damage, Australis was there to be a machine but could be subbed for utility.
Pre-emptives are the worst and must be planned for accordingly. Subbing in an off type delay/shield/heal makes all the difference. Amaterasu, Raphael, Echidna, Orochi, are all excellent on either team.
Some pairings did not work out, Panda, AALuci, Urd was ok but Paulina was better (same team compositions), my alt's box isn't as deep as my main so I didn't have a lot of options to poke around with.