Any pci-e type card in a pci-e x16 slot?

I believe that will be fine, but the physical size of the x16 slot will be bigger than a x4 or x8.

A PCI-E 1x slot should only be long enough to allow for 1x cards. The only way you can put in a 16x card is if the back is open so as not to physically block you inserting the card. Many modern motherboards have 16x length 4x or 8x slots that will allow you to insert a 16x length PCi-E card like a modern GPU. Anyway it will work and won't fry the system as long as the slot follows specifications and can supply the required power.

You can put in any PCI-E Card into a PCIex16, However lets say for sake of argument if you use a PCIE 1x card into a x16 slot it will only run in 1x mode.

Or if you put a x16 in a X8 it will on run at x8 speed.

All in all you should be 100% A ok