As the post description, one of my favorites have been the chemical name system as you can also map the names to numbers.<p><pre><code> Hydrogen - 1 - 192.168.1.1
Helium - 2 - 192.168.1.2 etc
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Another system I've been fond of is using the initial letter to be City names, but the leading letter corresponded to something (D - database, G - general purpose server, W - workstations, R - Routers). Not just cities, you can also extend this to car names, people names, or deities.<p><pre><code> Databases - Detroit, Dallas
General purpose - Gilroy, Giddings
W - Washington, Woodlands
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And another has been food which works if you have different sub-groups. For example groups can take on vegetables, drinks, fruits, meats, etc...