Order Maya Shelves. The pref keyword is set to xxx but you can set it to whatever and it'll keep any shelves that start with it in the front

shelfOrder.py

import maya.cmds as mc
import maya.mel as mm

gshelf = mm.eval("$temp = $gShelfTopLevel")
shelves = mc.tabLayout(gshelf,q=1,childArray=1)
sTotal = len(shelves)

pref = 'xxx'

sShelf = sorted([s for s in shelves if s.startswith(pref)]) + sorted([s for s in shelves if not s.startswith(pref)])


for i,shelf in enumerate(sShelf):
    i += 1
    sIndex = mc.tabLayout(gshelf,q=1,childArray=1).index(shelf)+1
    mc.tabLayout(gshelf,e=1,moveTab=(sIndex,i))