Is this a good pokemon diamond team for battle tower?
Kingra- blizzard, water pulse/surf, hydro pump, and toxic
Donphan- slam, fire fang, earthquake, iron tail
Probopass- rock slide, magnet bomb, lock-on, and zap cannon
Umbreon- faint attack, psychic, assurance, and last resort
Toxicroak- mud bomb, focus blast, poison jab, and sludge bomb
Forretress- rapid spin, take down, mirror shot, and spikes
Fail! You need a dragon type a fire type and a psychic type just as a principle
Maybe if you want to, take out Donphan for your starter, unless your started is Empoleon.
If your starter pokemon is Empoleon, trade him for Kingdra.
I'd take the Umbreon team. Attacks like Tocicroak's poison jab can cause major problems for some pokemon.
As far as suggestions go, I'd say probably three duo-types of grass, fire and water, since they just about cover everything and the second type would give an easier STAB.
Hmm well if i was you, i would go for a water fire and grass pokemon and attacks. Also you should try to put your starter as your first pokemon in the team.
But other then that your team is pretty good and i would think you should choose the first team.