a fire extinguisher and a smoke detector. ph up and down and some pippets. I use hydrogen peroxide for cleaning up around my plants and in the tent. It gets the job done and isn’t as unforgiving as bleach. it just turns to water and evaporates. get some mykos for the roots.
Depending on your location. yellow sticky traps. the list kinda goes on.
I had this cute list when I started my grow which at the time I thought was a lot. 
that ph meter is really important. I would get the apera ph 20 or 60 or a blue lab. the cheapos I hear arent great.
I would get some pot elevators but dont buy them from amazon. they shouldnt cost more than a couple dollars.