My preferred reading order:

“Clan Rathskeller” (short story) 
“Kaibab Unbound” (short story) 
Hounded
Hexed
Hammered
“A Test of Mettle” (short story)
Tricked
“Grimoire of the Lamb” (short story)
“The Eye of Horus” (short story #1 in Besieged)
“Goddess at the Crossroads” (short story #2 in Besieged)
“Two Ravens and One Crow” (short story)
“The Demon Barker of Wheat Street” (short story #3 in Besieged)
“Gold Dust Druid” (short story #4 in Besieged)
“The Chapel Perilous” (short story)
Trapped
Hunted
Shattered
“A Prelude to War” (short story)
Staked
“The Bogeyman of Boora Bog” (short story #5 in Besieged)
“Cuddle Dungeon) (short story #6 in Besieged)
“Purloined Poodle” (short story, Oberon’s Meaty Mysteries #1)
“Blood Pudding” (short story #7 in Besieged)
“Haunted Devils” (short story #8 in Besieged)
“Squirrel on the Train” (short story, Oberon’s Meaty Mysteries #2)
“The End of Idols” (short story #9 in Besieged)
Scourged