Suffixes are appended to item names to give additional information about the particular item or one of its attributes or to distinguish it from similarly named items.
Certain experiences are given a generic name and are given a suffix specifying which skill it will give experience to. Common examples are experience lamps from the Squeal of Fortune and fallen stars.
All standard potions can have 4 doses maximum; mixes can have 2; flasks can have 6. The remaining dosage is denoted with a number at the end (1), (2), etc. Potions created from (unf) potions are created as (3).
A number of items have a limit to how many times they may be used. Some of these items crumble to dust, like the ring of duelling or games necklace, while others simply lose the abilities it carried charges for. Those such items may have the option to be recharged, like a ring of wealth, or the charges may be a once-off use, like with the black mask. With any case, the number of charges on these items is denoted with the number in a parenthetical: (1), (2), etc.
All summoning scrolls for familiars in Dungeoneering are distinguished with a suffix for their tier as well, from 1 to 10.
All items in Stealing Creation are made from clay that is of 1 of 5 classes. As such, all items have the suffix (class #) to denote their class. The various skilling plots in Stealing Creation games also have a suffix to denote what type of clay they provide when collected from.
Beyond charges and dosage, numbers may be used to denote the quantity of an item, chronology, etc. For example: Alchemist's amulet fragments used numbers to display how many were in a single pile. Dungeoneering journals use numbers to order entries by date. Milestone capes use suffixes to denote the minimum skill level the player must have to wear it.
In the Artisans Workshop, all smithed items share the same basic name with the metal that constitutes the item being appended as a parenthetical: (iron), (steel), (mithril), (adamant), or (rune).
D&D tokens are all of the form D&D token (<activity/timespan>).
In Treasure Trails, all specific items (caskets, scrolls, puzzle boxes), will have the level of difficulty of the trail appended: (easy), (medium), (hard), or (elite).
Before the Evolution of Combat went live, items such as spears, arrows, bolts, and daggers could be poisoned. When poisoned, a suffix corresponding to the strength of the poison was appended to the name: (p), (p+), (p++), and (kp) for spears exclusively. In Bringing Home the Bacon, one of the pig dummies is poisoned with (p+++++) poison.
A handful of items have a suffix that is used only be that particular item or set of items. For example, each of the Address cubes have a different suffix that denotes which part of the room will be acted upon.