In reply to Dark-Cloud:
cassette tool and chain whip too if changing rear coggage. front mech cable alignment tool but prob get one in the box with the group set. Decent wire cutters and hex keys will just about do it then. Perhaps a pedal spanner but most have hex socket as well as spanner flats so may get away with a hex key (bit of pipe slipped on it for extra leverage)
Best tool i’ve ever bought for my bikes is a stand - easy, cheap, fast and does the job perfectly.
oh, you may need new bar tape for after you’ve changed the levers