Filtering and browsing several Traveller and user-preferred lists, here is a compilation of skills thought 'essential' for Traveller:
General (20)
Animal Handling
Battle dress
Brawling
Craftsman
Fleet tactics
Jack of all trades
Language
Leader
Liaison
Mechanic
Medic
Melee combat
Naval architect
Navigation
Prospecting
Recruiting
Ship tactics
Steward
Survey
Survival
ACADEMIC (3 + various)
Instruction
Law
Linguistics
Various Arts & Sciences
BLADE (type) (various)
BUSINESS (3)
Admin
Broker
Trader
CLANDESTINE (7)
Bribery
Carousing
Forgery
Gambling
Interrogation
Stealth
Streetwise
FIREARM (type) (various)
HEAVY WEAPONS (type) (various)
SOLDIER (5)
Combat engineering
Demolitions
Forward observer
Recon
Tactics
SPACE (6)
Astrogation
Engineering
Gunnery
Pilot
Vac suit
Zero g
TECHNICAL (6)
Communications
Computer
Electronics
Gravitics
Robotics
Sensor ops
VEHICLE (type) (various)
General (20)
Animal Handling
Battle dress
Brawling
Craftsman
Fleet tactics
Jack of all trades
Language
Leader
Liaison
Mechanic
Medic
Melee combat
Naval architect
Navigation
Prospecting
Recruiting
Ship tactics
Steward
Survey
Survival
ACADEMIC (3 + various)
Instruction
Law
Linguistics
Various Arts & Sciences
BLADE (type) (various)
BUSINESS (3)
Admin
Broker
Trader
CLANDESTINE (7)
Bribery
Carousing
Forgery
Gambling
Interrogation
Stealth
Streetwise
FIREARM (type) (various)
HEAVY WEAPONS (type) (various)
SOLDIER (5)
Combat engineering
Demolitions
Forward observer
Recon
Tactics
SPACE (6)
Astrogation
Engineering
Gunnery
Pilot
Vac suit
Zero g
TECHNICAL (6)
Communications
Computer
Electronics
Gravitics
Robotics
Sensor ops
VEHICLE (type) (various)