Welcome to the board. Lot of fun old gear there. I play with the vintage gear quite a bit so I can give you a good idea of what you have. The age of the gear is around the late 60s to early 70s, the tanks may be a little older judging from the valves. The first stages (part with the knob) appear to be a Dacor - not sure of the model and a Voit/AMF MR-12. The second stages (part with the mouth piece) appear to be as assortment from the same time frame. The Dacor first stage is a problem to service as the parts are getting hard to find, on the other hand the AMF/Voit is fairly easy to service as the parts are either common Orings or can be substituted with current Aqualung parts HOWEVER, you will not likely find a shop willing to service them because they can not get an official parts kit. The second stages use common parts and can easily be serviced, again assuming you can find a shop willing to do it. Most vintage divers do their own service work for this and other reasons. The ebay value of the regs is in the $10-20 range on a good day, I have paid a lot less.
The tanks are servicable (assuming they pass a couple of required test) but again, finding a shop that actually understands the tanks are OK to return to service is not always easy. value is in the $25 range, shipping will cost more so local sale is your best option
The BCs (that type is called a horse collar) are also usable assuming they are still in good shape. Odds are the black one is OK but the yellow one is almost certainly in bad shape internally. It may look good on the outside but the plastic parts inside of that particular one were very prone to getting brittle with age, I have yet to see one of those in good shape. ebay value on those is in the $10-30 range.
The mask may or maynot be useable depending on the condition of the rubber- $5 or so on ebay.
The rest of the stuff is useable with some value, lead is lead so it's obviously good and the knives are ok but nothing special.
Hope that helps.
