As Halcyon says one is an antiseize grease the other is a thread locking compound often based on the same "stuff" as superglue.
However the correct name of the former is Copaslip although often misspelled as copper slip or coppaslip. It is made by the makers of Molyslip. web page
Copaslip, suitable for temps up to 1100C. Assuming you are looking for something that will make them easy to undo. Not sure about its suitability in aluminium though. Maybe Alumslip would be better in Al.
One of the range of Loctite thread locking fluids if you want to stop them coming undone.
Depends on the mix of materials and if there is salt water in proximity. Not sure what you are trying to achieve but if you want to ensure they come out you need the correct anti sieze. Suggest you try This Link
As Vic suggests, Copaslip is the correct stuff to put on bolts securing an exhaust manifold. You can easily disassemble it years later. I've also been involved in restoring MG sportscars, and the rule was "never put in a dry bolt".
It is possible to use Loctite. However, beware, use the right version, code 242. Prevents rust in the threads, and the bond can be undone. Other versions are indeed like superglue...
For any work on exhaust manifolds then use copaslip or other similar.
Use it liberally on the stud threads before inserting the threads in the block and also on the nuts. If used also on the exhaust joint then you will find future maintenance a doddle.
The exhaust manifold will come off without torn knuckles or broken studs and the joint surfaces easily cleaned for re assembly. We saved hours on marine engine maintenance do as above.
one thing........make sure you do NOT put a big blob on the end of the stud thats going into the head, or fill the stud hole with oil. Just coat the threads on the stud.