These consumables have miscellaneous effects on players or enemies.
Most of these items still exist, but can no longer be obtained as drops or as purchases from the Nexus store. Most of these items were released for special holiday events. Historically limited edition items can be found here: link.
Mystery Bags turn into a random item when used, which depends on the type of bag.
Snowman Accessories are used to decorate snowmen in the winter Nexus.
Jack Frost Snowman Items appeared in RIFTS Season 4: On Thin Ice.
