In a nutshell, the forum rules are:
-Choose either A, the best team you can work with or B, the best team possible.
-Be sure to account for why this is the best team.
-Discussion is encouraged on ways to alter teams to make them better.
-Boss monsters are allowed in these teams, but clone monsters are not. (no 3 goldslime team)
-Finally, have fun and be creative, account for available skills and resistances. Enjoy!
My best team to work with is the team I currently use: lvl 98* Orochi +18, lvl 48* Metabble +9, and lvl 99* Grizzly +32. I have beaten the Master Monster Tamer over and over again with this group. My Metabble is immune to breath attacks and has 999 defense and does Cautious to use HealAll and HealUsAll every round while Orochi does Quadhits with 999 attack. My Grizzly also has 999 attack and supplements Orochi's attacking. Apart from being maxed out on stats, they have insane attack power and Orochi does as well. Metabble is the key player, however, due to the immunity, heal spells, and defense. Metaly, MetalKing, and Goldslime would work just as well if they had the spells as well I suppose.
I'm no master, but most people say the best team without clones is Goldslime, Darkdrium, and Deathmore 3. Others dispute that even Dracolord would be better than Dardrium, as Darkdrium is not immune to instant death. My team, as I have not reached this level of breeding yet, is Limited to Goldslime, Rainhawk, and Dracolord2