It depends on what type of bulk you want. I'm going to offer some examples that are limited to just new SV mons.
If you want Physical Bulk I highly recommend Dondozo. It has a base HP stat of 150 and a base Physical Defense stat of 115 and can hit really hard physically when needed with a base Physical Attack stat of 100.
Movset of Aqua Tail, Order up, heavy slam and bulldoze
If you want Special Bulk as a support mon, I'd suggest Clodsire. The Clod has base 130 HP stat, base 100 Sp. Defense. Its other stats are low, which is why i'd only recommend it for setting up hazards like toxic spikes.
Moveset of Toxic Spikes, Sludge wave, Rest and Spikes
If you want fast Bulk, Scream tail is the best way to go. Scream Tail has base 115 HP, base 99 Physical Defense, Base 115 Sp. Defense and Base 111 speed with both attack stats at a 65.
Moveset of Play rough, zen headbutt, crunch and substitute
An alternative for a hard physical hitting and bulky mon is Great Tusk, with a solid 115 base HP stat and a huge base 131 in both Physical Attack and Physical Defense. Yes the special side does suffer but Great Tusk does have a base speed stat of 87.
Moveset of Earthquake, Knock off, Close Combat and Megahorn.
Hope this helps.
