Basic hand tools, first and foremost, a sheet metal hammer, (not something you think will do as a SM hammer; get a real one.... Two of my closest friends were in the trade for decades, and both worked as formen and superintendents, and if a guy showed up on a job without a sheet metal hammer, they would send them back to the hall...)
You will also need a rivet set, not to set rivets, but to lock certain seams (I don't recall the official name.. Sorry)
The small one I show is sufficient, but a bigger one or something bigger to use as a dolly is a nice to have...
These are nice to have, you can also get the top set in vise grips as well, the bottom set I made from a set of nippers with crunched jaws. these are VERY good for flattening munged edges of metal. as they produce a lot of pressure due to the short distance between the pivot and the work. (Archimedes lives on!)
If you make a set, clamp down n a couple of thicknesses of 22 or 24 ga, so the jaws are spaced better.
You said snips but there are a lot of types:
Bench - The aluminum are nice if you are cutting all day, but are more limited on the thickness you can cut. If you can find then still, a set of "specials" (not shown) is nice to have. longer handles and the jaws are better for SS and alloy steels.
Look up my thread on Tin Snips 101" for more on snips (inc pics and info on the specials).
Aviation snips right left and straight:
The notchers are a nice to have, as are the angled snips, but you will need them eventually:
And the lowly pop riveter, these are older, but make sure you get good ones.
I don't remember the specific name for these (shinker? Malco C-1...) If you are doing ducting, you need these to make the shrunk end when you shorten a length of duct at times.