1) Baby Wipes
Nope not for wiping bums (although occasionally you need to wipe a puppy bottom) but for your hands after class, walks, a few hours in the park. Between getting things out of their mouths, the treats that smell like baconcheesemeatsalmonstuff. and picking up their "potties", having wipes in your bag, in the car, at home, etc. make it all a bit more manageable and don't leave you looking for a sink when there likely isn't to be one around. The Target Up & Up brand is affordable and does the job just fine.
2) Kongs- Many of them!
I can't believe that until Stanley we never bought a Kong for one of our dogs. Maybe we did and they just weren't interested in it, but these have been a total necessity with Stanley. We started off with the small size, and now have a few smalls and a medium. It helps to have many since they are bit challenging to clean and take time to "stuff" so having a few during the week really help.
3) Peanut Butter
Just buy stock in Jif now. Seriously. Or go to Costco and don't second guess the package that has two HUGE tubs of it. We use this for just about everything! Primarily we stuff kongs with it, freeze them with a bit of kibble mixed in and it can keep the pup entertained for at least 20 minutes. We also smear it on our hands and let him lick it off while trying to brush him, since he HATES being brushed! I also have this toy for Stanley, and after many uses I got smart and realized I could fill each compartment with some PB, freeze it and it lasts even longer than a kong if I need some peace and quiet.
4) Target Pee Pads
Don't buy the expensive pee pads made specifically for potty training. First, they are CRAZY expensive. Second, most are scented to entice your puppy to pee on them rather than the rest of your floor. Which is great if you are paper training your little furmuff, but I didn't want Stanley to think going inside under any circumstances was ok. Enter the Up & Up brand of pee pads that are not scented and way way way cheaper. The first weeks of Stanley's life, these were an absolute must! Now we have a bunch left over, but I line his crate pad and bed with them just in case since he is still a tad unreliable about his bladder control.
5) Swiffer Wet Pads
While I am married tot the steam mop concept and am sure I will never live without one ever again, turning it on, making sure you have a decently clean fabric pad and water in the tank can be a bit time consuming. When your puppy just released Lake Michigan on your floors, you need something a bit faster. Luckily, I kept the gold ol' swiffer and pulling out a wet pad to quickly sop up the mess before little paws can step in it and track it everywhere else has been huge. I steam mop later to just disinfect a bit more and get the chemical residue off the floor that I am not a fan of, but the quick clean-up is essential when a bounding, energy-filled pup.