Everything is on the steel standard. See Materials for different ratings for mateirals.

Full Armor :
Cloth-of-metal +2/+2
Light mail +3/+3
Karuta +3/+4
Ring mail +4/+4
Chain mail +5/+5
Reinforced mail +6/+5
Lamellar +6/+6
Totami +6/+6
Elven cloth-of-metal +6/+6
Laminar +6/+7
Scale mail +7/+7
Disc mail +7/+8
Splint mail +8/+8
Plate mail +9/+9
Jousting plate +10-/+9
Molded mail +10/+10 (literally a second, magically metallic skin)
Exoskeleton +11/+11

Pieces of mail :
Face: Face-coverings vary mostly by how much they cover. The more they cover, the better the blocking bonus, but the worse the visibility penalty.
Rim-faced: covers outer face, not mouth, nose or eyes. +1/+1; +1; no visibility penalty.
Slitted visor: thin slit for eyes; +2/+2; +3; -3.
Cross-visor: a cross-shaped slit; +2/+2; +2; -2
Mask-visor: covers eyes but not mouth or nose, has small eye holes. +1/+1; +2; -1
Wide slit visor: a larger slit for the eyes. +2/+2; +2; -2.
Cage visor: bars across the face. +2/+2; +2; -1.
Mouthpiece: covers mouth but not eyes. +1/+1; +1; no penalty.

Helms: Helms have ratings for stun/wound for light, medium, and heavy construction, and for blocking bonuses. Numbers given are just for light construction; add +1/+1 for medium and +2/+2 for heavy.
Helms come in several broad categories:
Caps: simple head-coverings that do not cover the face or neck. +2/+2; +1
Skullcaps: only cover the top of the head. +1/+1; +0
Jointed helm: any form of helm, but with multiple pieces, giving it a little less toughness. +1/+1; +1
Closed helmet: covers face and head. +3/+3; +2
Close helm: covers face, neck, and head. +3/+3; +3
Great helm: covers face and head; very heavy. +4/+4; +2
Brimmed: cap with brim. +2/+2; +2
Winged: helm with sideburn-style guards. +3/+3; +2
Horned: any sort, but with horns. Same as whatever sort of helm it is. Horns are +1 intimidation and weapons (modifiers vary by material).
Visored: optional face-covering. +2/+2; +3 if visor down, +2 if not.
Necked: protects neck but not face. +2/+2; +2
Coif: chain coif, protects neck. +1/+1; +2
Crown: circlet that protects only part of the head; with spikes to help deflect head shots, but opened so that it is less over-hot. Impractical. +1/+1; +1
Crowned helm: close helm with spikes to deflect head shots. +3/+3; +2

Neck: neck coverings include gorgets and bevors and so on. They get block bonuses and stun/wound scores, but they can limit cranial mobility.
Collar: at the top of the torso piece, this leaves a gap between chest and face, but narrows it. +1/+1; +1; no mobility penalty.
High collar: same as collar, but bigger. +2/+2; +2; -2.
Beard: hangs from helmet over front neck. +1/+1; +2; -1.
Tail: hangs from helmet down back beck. +1/+1; +2; -1.

Body armor: body armor has the same modifiers as full armor, but block modifiers for how much it covers. Below terms are broad descriptions; specific styles may vary in modifiers.
Codpiece: covers the genital region. +1 block, no mobility penalty. Might result in being made fun of.
Tail: covers the buttocks; +2 block, -1 mobility.
Skirt: covers midsection all around; +3 block; -1 mobility.
Bellyband/armor: covers the belly region. if just front or back, it's +2 block, -1 mobility; if all around, it's +3 block, -2 mobility.
Breastplate: covers the chest. if just front or back, it's +2 block, -1 mobility; if all around, it's +3 block, -2 mobility.
Mantle: covers the shoulders. if just front or back, it's +1 block, -1 mobility; if all around, it's +2 block, -2 mobility.
Vest: covers shoulders, chest and belly region. if just front or back, it's +3 block, -1 mobility; if all around, it's +4 block, -2 mobility.
Skirted vest: covers shoulders, chest, belly, and midsection. if just front or back, it's +4 block, -2 mobility; if all around, it's +5 block, -3 mobility.
Mail shirt: covers shoulders, chest, belly, and arms. if just front or back, it's +4 block, -2 mobility; if all around, it's +5 block, -3 mobility.
Coat: covers same as shirt, but goes over other armor. Adds +2/+2 to toughness at steel standard.
Long coat: covers same as coat, but also includes upper thighs. Adds +2/+2 to toughness at steel standard

Arm and Leg pieces: These are broad descriptions of how much and what they cover up.
Pauldron: shoulder guards. +1 block, -1 mobility.
Bracer: forearm guards. +1 block, no mobility penalty.
Besagew: armpit guards. +1 block, -2 mobility.
Couter: elbow piece. +1 block, -1 mobility.
Rerebrace upper arm guards. +2 block, -1 mobility.
Fingerless gauntlet: covers hands but not fingers. +1 block, -1 dexterity.
Gauntlet: full hand cover. +2 block, -2 dexterity.
Mail sleeve: full arms. +3 block, -2 mobility.

Barding: This is armor for mounts. All block bonuses and mobility modifiers are the horse (or hippogriff) standard.
Full barding: every possible part protected. +5; -5
Forward barding: Just the head and forelegs. +3; -3
Rear barding: Just the rump and hind legs. +3; -3
Body barding: just the middle body. +4; -2
Saddle: just the saddle area. +2; -1
Wing barding: just the wings. +2; -4
Leg guards: just the legs. +1; -3
Head barding: just the head. +3; -1; might also include visibility modifiers.
Neck barding: just the neck. +2; -1

Shields : block bonuses depend on size. An ogrish shield counts as a kite shield to an ogre, and a giant shield counts as such to a giant (and so on), but the block modifiers given are those for humans.
Buckler: +1 block. Required STR 3 for no mobility penalty.
Targe: +2 block. Required STR 6 for no mobility penalty.
Parma: +2 block. Required STR 6 for no mobility penalty.
Aspis: +2 block. Required STR 6 for no mobility penalty.
Heater shield: +2 block. Required STR 7 for no mobility penalty.
Kite shield: +3 block. Required STR 10 for no mobility penalty.
Riot shield: +4 block. Required STR 10 for no mobility penalty.
Scutum: +5 block. Required STR 13 for no mobility penalty.
Ogrish shield: +6 block. Required STR 16 for no mobility penalty.
Ogrish scutum: +7 block. Required STR 18 for no mobility penalty.
Giant shield: +8 block/. Required 19 STR for no mobility penalty.
Shield wall: +9 block (formation; movement impossible for block bonus to be in effect)
Giant scutum: +10 block. Required 22 STR for no mobility penalty.