Not even reading the thread, going front-to-back (twss):

15mm open-ended wrench
assorted metric allen wrenches
chainring bolt spanner
chain whip
lockring tool
torque wrench
allen, hex sockets (metric)
spoke wrench
appropriately sized cone wrenches
tire levers
chain tool

Those are the basic "maintenance" essentials. If you want to get into tools for full assembly, then you need to add:

Headset press (homemade or professional)
crown race setter (homemade of professional)
mallet
crank puller
bottom bracket tool
pedal wrench

On the go? All you need is:

multi-tool (I like the Crank Bros. m17)
Trixie
stubby adjustable wrench
tire levers

Even with this (mostly) comprehensive list, I can think of about a dozen other cases where I would need more specialized tools.