Vehicles:
For vehicles in battletech 2300, we have numerous sources in the fluff from the earliest vehicles in each class that these primitive designs were themselves replacing an even older version of the same kind of vehicle. So for each of these Canon vehicles, I went in and built a Tech B year 2100 version, a Tech C year 2200 version, and a Tech D year 2300 version. The reason for 3 tech levels is because independent and periphery powers often have only tech B manufacturing, putting them at a 2100-2199 year levels. The proto-houses and shipping conglomerates that all eventually merge to the great houses are better developed and can produce Tech C manufacturing and ship it to their lower tech worlds, putting them at year 2200-2299 year levels. The Terran Alliance of course has the highest tech, but also suffered from infighting that left all but 20ish worlds (from 600+) supported. So they have a mix of year 2300 tech, gradually getting worse the further outside the 'supported' 30 light year sphere you are.
10 ton APC. Has a machine gun in a turret with basic fire control (2 tons) and 1 ton for infantry support, with max armor for the chassis. Variants remove the weapon for a 3 ton cargo or MASH bay.
Year 2100: Wheeled chassis, BAR 4 armor, 3/5 speed.
Year 2200: Upgrades to Tracked chassis, BAR 5 armor, still 3/5 speed.
Year 2300: Terran Alliance Hover chassis, BAR 5 armor, 7/11 speed
Year 2390: Canon APC (all types) BAR6 armor, Tracked gets +1 mgun, Wheeled gets 4/6, off road, and +1 mgun
Colonial Marines: 15 tons, 4/6 Wheeled (Fuel Cell), 31 points BAR2, Light Cannon (18 Shots), Mgun, Advanced FC, 2 Ton Infantry Bay
10 ton Attack Vtol. Has a machine gun and 4 rocket pods. Max armor for the size, basic fire control.
Year 2100: 5/8 speed, BAR2 armor, 10.5 tons
Year 2200: 8/12 speed (Fuel Cell)/ 6/9 (ICE), BAR4 armor
Year 2300: 10/15 speed (Fuel Cell)/ 8/12 (ICE), BAR5 armor
Year 2371: 7/11 (ICE) Strike Falcon, 30t, BAR7, 6t Infantry bay, replaces 'Bird of Prey'
55 ton AWACS. Has all 3 types of Satellite Imagers, 7 tons of communication equipment
Year 2100: 3/5 Support Vehicle (ICE), max BAR2 armor.
Year 2200: 4/6 Primitive Aerospace fighter, 14 tons armor
40 ton Heavy Fighter. Has mgun and 12 ton internal bomb bay, ICE engine for MACH2 supercruise
Year 2100: 3/5, 40 points BAR2 armor
Year 2200: 4/6, 41 points BAR3 armor
Year 2300: 5/8, 44 points BAR3 armor, Advanced Fire Control
Year 2354: Colt Medium Fighter. 5/8, 44 points BAR5 armor, 4 hardpoints, 2 LRM5, AFC
Year 2328: Vendetta 'Medium' Fighter. 60 tons, 5/8 Fusion (MACH3 Supercruise), Armored Chassis, 54 points BAR10! Armor, AFC, L Laser, 2 M Laser, S Laser, 6 External Stores
80 ton Heavy Tank. Armored Chassis, Advanced Fire Control, max armor.
Year 2100: 2/3, BAR5 armor. 2 Mgun, 2 RL10, 2 VGL, Heavy Cannon with 24 shots
Year 2200: 3/5, BAR7, same weapons
Year 2310: Estevez MBT(Davion), drops 2 RL+Advanced FC for 42 shots instead of 24
Year 2295: 3/5, BAR7, 2 Mgun, 2 VGL, Prototype AC5, Prototype LRM10 (Merkava IV?)
Year 2384: Merkava VI, 75 tons, 80 points BAR7 armor, AC5/SRM4/LRM10/Mgun
30 ton Heavy Transport VTOL, max 34 points armor
Year 2100: 6/9, BAR2, 9 tons Cargo or 3 Arresting Hoist (45 ton lift)
Year 2317: Cobra Vtol Transport. 8/12, BAR6, 9 tons Cargo, 5 MGUN + Advanced FC
40 ton Hovertank. 7/11 (ICE) max armor (44 points)
Year 2200: BAR6 armor, 8 tons cargo (Hover Vehicle Transport/HVT-1?)
Year 2300: BAR7 armor, AC5, Primitive LRM5, Turret, Advanced Fire Control (LTV-1?)
Year 2298: Ashur Hoverscout: 45 tons, 8/12, 49 points BAR7, 2 LRM5, 3 Mgun, Vflamer
25 ton Light Fighter/Attack. MGUN+6 tons Internal Bomb Bay, ICE engine (MACH2 Supercruise)
Year 2100: 3/5, 20 points BAR2
Year 2200: 4/6, 29 points BAR2 armor
Year 2300: 5/8, 26 points BAR3 armor
Year 2297: Hurricane. 6/9, 29 points BAR5, Mgun+RL15, 2 External Hardpoints
Year 2302: Mosquito. 6/9 Fusion (Supercruise MACH3), 24 points BAR6, LRM5 + 2 MGUN, 2 External Hardpoints
65 ton Main Battle Tank. Armored Chassis, max armor, advanced fire control
Year 2100: 2/3, BAR5, 3 VGL, Mgun, Heavy Rifle, 18 shots
Year 2200: 3/5, BAR6, 3 VGL, Mgun, Heavy Rifle, 24 shots
Year 2240: 3/5, BAR7, 3 VGL, Mgun, Prototype AC5, 30 shots
Year 2396: Marsden I, 3/5, BAR7, SRM-6, Mgun, AC5, 3 tons ammo total
Year 2384: Merkava VI, 75 tons, 80 points BAR7 armor, AC5/SRM4/LRM10/Mgun
50 ton Medium Tank. Max armor, Advanced Fire Control
Year 2100: 3/5, BAR3 Mgun, RL10, Medium Rifle, 12 shots
Year 2200: 4/6, BAR5 Mgun, RL10, Medium Rifle, 12 shots
Year 2300: 5/8 (Fuel Cell), BAR6, Mgun, RL10, Prototype MLAS, (KVN-1)
Year 2367: Korvin KVN-2, 5/8 (Fusion), BAR6, Mgun, LRM-5, Large Laser
30 ton Mobile Tactical Command/Jamming. Wheeled Chassis, Off Road, 7 Tons Communication
Year 2100: 3/5. 3 Tons Infantry, 60 Points BAR2
Year 2200: 4/6. 3 Tons Infantry, 64 Points BAR4
Year 2317: Dunning Mobile Tactical Command Post. 5/8, 64 points BAR6, 3 Tons Infantry
Refueling Plane. 55 tons. Fluid Suction, Refueling Drogue
Year 2100: 3/5 ICE, 55 points BAR2, 17.5 ton Liquid Cargo
Year 2200: 4/6 Primitive Aerospace, 69 armor, 25 ton Liquid Cargo, Improved Smart Robotic
Infantry Fighting Vehicle. 3 Ton Infantry Bay, Armored Chassis
Year 2200: 3/5, 25 tons, 3 mgun, 54 points BAR6, Basic FC
Year 2284: Chi-Ha Infantry Combat Vehicle, 22t, 3/5, 48 points BAR5, 3 mgun, B FC
Year 2352: Chi-Ha Infantry Combat Vehicle, 22t, 4/6, 48 points BAR6, 3 mgun, A FC
Various Support Unit
Year 2100 Support Truck 25 tons, 4/6 Wheeled, 54 points BAR4 armor, 5.5 tons equipment
Ambulance: Mash Unit (1 Theater) Paramedic (4) 1 Ton Cargo
Tractor: Tractor (1.5 tons) 4 Tons Cargo
Crane: 54 points BAR3 armor, 2/3 speed, 4 Lift Hoist (50 ton lift capacity)
Year 2341 Carter Medical Emergency Response Vehicle 25 tons 5/8 Wheeled Off-Road, 52 points BAR6, 4 Paramedic, MASH 2 theaters, 2 tons cargo
Year 2300 Randolf Support Vehicle, 35 tons, 4/6, 62 points BAR5, 3 Mgun, Basic Fire Support, Tractor, 9 tons cargo
Year 2250 Stoat Scout Car, 15 tons, 5/8 (Fusion) Wheeled Off-Road Armored Chassis, 31 points BAR7, 1 Mgun, Basic FC, 1t Communications
30 Ton Self Propelled Thumper, Wheeled, Thumper Cannon with 60 shots
Year 2100: 1/ 2 speed, 40 points BAR2
Year 2200: 2/3 speed, 62 points BAR2
Year 2300: 3/5 speed, 64 points BAR2, Advanced Fire Control
Year 2321: Reaper Self-Propelled Artillery, 3/5 Tracked, A FC, 72 points BAR6, Slas
60 Ton Weapons Carrier, Tracked
Year 2100: 3/5 Armored Chassis, 79 points BAR5, B FC, (10xRL10) OR (11xMine Launchers)
Year 2200: 3/5, 62 points BAR6, B FC, SNIPER with 40 shots, (2295 2 LRM-20 with 24 Shots)
Year 2321: Apostle Self-Propelled Artillery. 80 Tons, 3/5 Tracked, 104 points BAR6, Slas, Sniper with 30 shots, A FC
Year 2300: 3/5, 78 points BAR6, A FC, 4 Primitive AC2 with 4 tons ammo
Year 2440: Primitive AC/2 Carrier, 4 AC/2, 2 tons ammo, A FC, 78 point BAR6, 55 tons