Menoram doesn't run a shop per se; all items created here are for the use of the people at Finarfin and their allies. Members of the adventuring group could make purchases or place orders here, though it is a bit out of the way.
All of the potions in the DMG, plus those listed below, can be made here.
Elixir of Life
Fire Breath
Oil of Acid Resistance
Oil of Disenchantment
Oil of Earth Elemental Invulnerability
Oil of Fire Elemental Invulnerability
Oil of Water Elemental Invulnerability
Oil of Firey Burning
Oil of Timelessness
Potion of Rainbow Hues
Potion of Vitality
Potion of Cold Resistance
Potion of Patriarchism
Potion of Necromancy
Potion of Thievery
Water of Youth
Geriatric Oil
Frost Breath
Chlorine Breath
Oil of Impact +6