Proficiency

My weapon types are copied directly from Spells & Steel, seen here: https://spellsandsteel.blogspot.com/2012/09/weapon-behaviour-simplifying.html
As a HEMA practitioner (or former practitioner), he has some excellent insights into weapon behavior and combat mechanics, and I would highly recommend the blog if you have as much interest in this stuff as I do.

I will restate the weapon types here in my own words:
Light weapons: dagger, knuckles, kama, katar, cudgel, etc. Possibly whips as well.
Balanced weapons: arming sword, long sword, spear, bo staff, etc.
Mass weapons: axe, mace, flail (if you decide to include them), hammer, etc.
Reach weapons: poleaxe/polehammer, greatsword, etc.

The general jist of it is pretty easy to understand. For damage, it will always be dealt in increments of d6. Light weapons deal the lower of 2d6, and other weapons will deal 1d6 if one handed, or the higher of 2d6 if two handed. Strength bonus is always added

Everyone is proficient with light weapons, with possible exceptions for particularly exotic ones, and combat trained classes get proficiency with all melee weapons and armor. They can choose to exchange one melee proficiency for one rank in a ranged skill. Combat capable classes get one choice of melee or ranged proficiency, and one choice of armor or shield proficiency.

If wielding a weapon that you are not proficient with, you cannot parry or feint with it. Each character can have one personal weapon to become proficient with, after they have dealt damage with it to three different foes. This only applies to that specific weapon, not other weapons of its type, and if they decide to become personally proficient with a new weapon, they are no longer proficient with the previous one.

Unarmed attacks deal 1 damage plus strength bonus by default. With martial arts training, you can parry unarmed attacks while unarmed, and deal the lower of 2d6. With martial arts mastery, you can parry weapons while unarmed, and deal the higher of 2d6.

For ranged weapons, I would have two skills; archery and throwing. Each range increment incurs cumulative a penalty of -1, and trick shots require a difficult check. Range increments would generally differ depending on the weapon. Perhaps a third skill such as 'firing' for crossbows and guns, but these would be rare and expensive, unavailable for a new character.

Starting classes

Class format is based heavily on the GLOG format from Goblin Punch. That being said, while I borrow a few things from the GLOG core rules, the combat system (to which most of these are related) is completely different.

Infantry

Fight well on a team. Combat trained.

• Stat bonus: +1 blocking defense every level
• Starting items: chainmail, large shield, spear, lucky charm
• Skill: archer, surgeon, or tactician

Level 1: phalanx, siege diet

Level 2: team attack, mentor

Level 3: squad support

Level 4: heroic sacrifice, rally

• Phalanx: when you block alongside allies in the same engagement, gain +1 defense for each ally, and +2 for each infantry ally blocking with you.
• Siege diet: you can split your meals with an ally to each get by on one ration per day.
• Team attack: gain +1 damage for each ally engaged with the same target in the same round.
• Mentor: if you have fought alongside an ally through at least one level up, once per encounter you can perform one non-magical technique they have performed during the same encounter, including skill checks if you have the same skill.
• Squad support: if an ally within reach would take damage from a ranged attack, you may take their place.
• Heroic sacrifice: whenever an ally in the same engagement would take a wound, you can choose to take the damage in their place.
• Rally: once per day, call out inspiration to your allies to restore 1d6 hit points to all who an see or hear you.

Thief

Use stealth, skill, and luck to steal. Combat capable.

• State bonus: +1 stealth every level
• Starting items: blackjack, dark cloak, manacles with key
• Skill: sleight of hand, jeweler, or panhandler

Level 1: thievery, change hands

Level 2: lucky, stash

Level 3: slippery

Level 4: very lucky, great escape

• Thievery: gain the locksmith and pickpocket skills at rank 1.
• Change hands: once per session, you can declare that you retroactively swapped items with another character in the party, no matter how separated you are.
• Lucky: once per day, reroll any 1d6 roll immediately after the result has been seen. Can be used for damage, a skill check, or any other 1d6.
• Stash: by storing treasure in a hidden way, you can keep up to half of your next level's worth of treasure safe from other thieves at night or during the day.
• Slippery: get a +5 bonus to speed when retreating out of a melee engagement.
• Very lucky: reroll up to two additional 1d6 rolls, as lucky.
• Great escape: once per day, you can instantly escape from anything you could plausibly have escaped from, no matter how difficult it would have been.

Hunter

Specially skilled in subduing large beasts and laying traps. Combat capable.

• Stat bonus: +1 to stealth every two levels
• Starting items: hunting knife, trapping kit, bow, quiver, animal skull
• Skill: survivor, butcher, or archer

Level 1: trapper, astride

Level 2: wrangle

Level 3: provoke, fast trapper

Level 4: steer

• Trapper: improvise traps outside of combat to either halt, damage, or create an alert when passed through. You must spend an hour in the morning preparing your trapping kit. More elaborate or effective traps could be made using specific materials at GM discretion.
• Astride: climb on top of large beasts to strike vulnerable areas for a guaranteed hit, along with a +3 damage bonus. Beasts can spend their turn attempting to shake off a hunter with a strength save, but if the hunter spends their turn clinging on, it becomes a strength contest.
• Wrangle: using a rope, attempt to tie down a beast with a strength contest. Anyone can contribute to this contest, but any non-hunters will be knocked prone if the beast wins instead. Any tied down beast will remain prone until it can succeed a difficult strength save.
• Provoke: take an action to impel beasts into charging at you. They will take 1 damage if you are beside a wall when you do this.
• Fast trapper: once per encounter, a trap can be improvised during combat. This takes one full round, accounting for movement to lay tripwires or hazards.
• Steer: while astride, a hunter can force the beast to move if they succeed on a strength contest.

These are the three classes I recommend having available from the start, to ease players into the game, and to facilitate a lower starting power level and magical scale. After they play for a bit, and do various interesting things, I recommend opening up class options, including magical classes which will be detailed in a later post.

Skies Below

The current working title for my homebrew game is Skies Below. And of course, I've thought of a new combat system for it. My goal with designing a combat system is for it to be logical, simple, and dynamic.
This one includes three main attack options; press the attack, parry and counter, or feint and follow through. These work similar to rock-paper-scissors, except that while anyone can press, you can only parry with a weapon, and only combatants with training can feint. Additionally, anyone with a shield can block, increasing their defenses for the round.
If your attack beats your opponent's, you deal 1d6 damage modified by weapon type, plus strength modifier, and reduced by their defense. If you pick the same attack as your opponent's, you deal 1 damage plus your strength modifier, reduced by their defense.
Beasts and other unintelligent combatants can lunge (as press), or latch on (as parry), and typically cannot feint.
This system works well because the attack choice can essentially replace the attack roll, though it doesn't include provision for critical attacks. That's the main thing I want to consider in the future. For ranged combat, it's simply going to be a skill, either archery or throwing.

Autobiomancy

This strange and terrifying art entails the practitioner seeming to summon her own organs and bodily parts as twisted monsters to fight or act on her behalf. The power held by these organ-creatures varies, but the autobiomancer is left without the use of whichever part she has summoned until it is dismissed. Most often this is used with the hands, an eye, or occasionally the entire skin, though there is a legend of a summoner sacrificing her life and summoning her very heart to wreak havoc.

Examples
Fingernails- summoned as a dagger.
Eyeball- capable of rolling, can still see through it. About the size of a melon.
Hand- can crawl and tackle people. About the size of a dog.