Quote from IAMBaldur888
I have not seen any slimes in swamps.
The fire resistance potion is brewed with magma cream that comes from magma cubes and they are only in the nether.
Quote from fmn335
You can also make Magma cream using Slimeballs and Blaze powder but its good to know the Magma Cubes drop em too. I already knew about the fire resistance brewed with Magma cream too bud.