Try GNW Neji/Neji, Sasuke, Tsunade and Guy for a six combo + buff on Neji, Sasuke and Guy from Sasuke's field.Both Guy and Sasuke get sneezed on and die, so I'm not entirely sure how viable this will be against some opponents.

Shizune, Tsunade, Chiyo and Hinata for a 5 combo team, Chiyo will always start combo as long as her puppets are up, but it really won't work for higher level trials. It's an option, but without a targeting mystery I don't see it working too well.

Shikamaru, Baki, Hinata and Tsunade for a 5 combo (sometimes 6) team that activates off of Baki's mystery. You can replace Shikarmaru with Shizune and the combo will be the same, besides the lack of a character standard attacking, and more poison to the team.

I could probably figure out some more later. I hope some of these formations are useful to you!