The "Dracpack" is a resource pack made by Draccy. It is composed of nearly 100% custom assets, including textures, models and sound files. It has been in development for as long as Minecraft has supported texture packs. Most additions to the pack are made with consideration for how they will be experienced on Draccyserv.
The pack started in 2010 as a modification of the Painterly pack (dubbed "unpainterly"), which at the time was a very simple texture pack. It eventually became known as the Dracpack as, over time, every asset was replaced with custom designs.
As the game developed, new features were added that were far outside the scope of the original painterly base. From this point forward, every graphic became an original any new ones were designed from scratch as the game developed.
(to be expanded)
The Dracpack now includes special models and textures around which numerous server features have been designed. As a result, other resource packs are in effect incompatible with Draccyserv. We require the use of the Dracpack so that custom objects (like Warp Pipes), special sounds and paintings are visible to all players.
Some players have favorite packs that they really insist on using. In the future, there will be a "Dracpack Lite" that can be loaded on top of other packs to override features where necessary. There's no certainty as to when this will be available.