Unavailable Skills
The following skills from Basic Set, Low-Tech, and Martial Arts are unavailable, whether because they rely on technology above the game's TL, because they've been replaced by other skills or by advantages, or because I just can't see them showing up in play. In short, anything reliant on TL2+ technology is unavailable. Anthropology; Armoury (Battlesuits, Force Shields, Small Arms, or Vehicular Armor); Artillery (Beams, Bombs, Guided Missile, or Torpedoes); Beam Weapons; Bicycling; Bioengineering; Biology; Boating (Large Powerboat or Motorboat); Brainwashing; Chemistry; Computer Hacking; Computer Operation; Computer Programming; Crewman (Airshipman, Spacer, or Submariner); Driving; Electrician; Electronics Operation; Electronics Repair; Engineer (Electrical, Electronics, Materials, Microtechnology, Nanotechnology, Parachronic, Psychotronics, Robotics, Small Arms, or Temporal); Enthrallment; Environment Suit; Exorcism; Expert Skill (Computer Security, Conspiracies, Egyptology, Epidemiology, Hoplology, Hydrology, Political Science, Psionics, Thanatology, or Xenology); Explosives; Fast-Draw (Ammo); Force Sword; Force Whip; Forensics; Forgery; Forward Observer; Free Fall; Geology; Gunner; Guns; Hazardous Materials (Biological, Chemical, or Radioactive); Hidden Lore (Faerie Lore); Linguistics; Liquid Projector; Mathematics (Computer Science, Statistics); Mechanic (anything listed in Engineer, above); Monowire Whip; Musical Instrument (Bagpipe, Bell, Bullroarer, Didgeridoo, Double Reed, Dulcimer, Fiddle, Hurdy-Gurdy, Jew's Harp, Keyboard, Large Concussion, Mbira, Psaltery, Rebab, Serpent, Single Reed, Trombone, Tuned Drum, or Tuned Percussion); Navigation (Space); Paleontology; Parachuting; Pharmacy (Synthetic); Photography; Physician; Physics; Piloting; Propaganda; Psychology (Experimental); Savoir-Faire (Police); Scuba, Shiphandling (Airship, Spaceship, Starship, or Submarine); Skating; Smith (Iron); Sociology; Submarine; Thaumatology; Typing; Weird Science. In addition, certain specialties of Engineer (Vehicle Type) and Professional Skill are unavailable. If you are unsure, ask the GM.
Anachronistic Skills
The following skills from Basic Set, Low-Tech, and Martial Arts can be taken, but only if you have Gadgeteer or the Anachronistic Skill perk (one per skill). Armoury (Heavy Weapons); Artillery (Catapult); Crossbow; Cryptography; Engineer (Artillery or Clockwork); Lockpicking; Mathematics (Cryptology or Pure); Mechanic (Clockwork); Metallurgy; Physiology; Smith (Copper or Lead and Tin).