Puppy pads, great for training, once they have got used to them move them outside.
Crates work well for some dogs, but personally I would advise against locking them in until they are using it of their own free will.
Poo bag holder that you can put on a lead. Nothing worse than being caught out.
After a few weeks puppies tend not to to wee/ poo near where they eat or sleep if they can avoid it. So it's good to keep these areas separate if you can.
Also works as a deterrent, i.e. if the dog wees on the landing, put there dog bowl there for a couple of days, it usually stops them.
Collar and name tag plus spares.
Consider a harness for dogs that can escape from a collar (i.e. ones with small heads (brains)). If in any doubt think about your dog running loose in the middle of a busy town.
Consider a dog flap
Treats and a whistle, start recall training (bribery) within a few weeks.
Consider cargo grill if dog is large and you have suitable car with a boot.
Mix with as many dogs as possible (after vacs), and expose the pup as much as possible, car journeys, busy streets, pubs and fireworks etc. they usually just assume it's part of life. and it makes life so much easier later.
Unless you're able to finance unexpected vet bills, I would recommend considering insurance.
Decide now, is the dog allowed on the furniture or not?
Decide now, do you feed the dog only in their bowl, or will you feed random scraps off your plate, and live with the possible consequences of them pestering you?
Make sure the puppy knows you're the leader of the pack.
Difficult, but a try to leave them alone a bit as well.
I hope you have many years of love and good times with your puppy.