This is not really meant to be an in depth guide, but rather a way to tell what Manuals do what at a glance. That said, I will give a few pointers and clarifications here before the table proper:

Each Character can use 3 manuals concurrently once sufficiently reincarnated. Manuals do NOT need to match an adventurers weapon, though they will lose out on a small attack boost for using a mismatched manual.

To expand on that: all manuals boost the attack strength of their corresponding weapon (both phys and mag). If attack is listed in the table below as a boosted stat, the manual grants an additional, universal bonus regardless of equipped weapon.

Two very important clarifications:
"Sword and Spear" manuals apply their bonuses to "Firearms" class weapons. This appears to be a translation issue.

Axe manuals however do not appear to have a corresponding weapon, and Hammers currently have no skill manuals. It is possible these are meant to apply to each other but are bugged and mistranslated.

Very loosely ranked:

• Staff - Easily the strongest and most versatile weapon type. Dps? Buffs? Medic? Summoner? Staff can do it all. Hardest part is picking only three manuals.
  
  
• Dual Sword - The auto crit from Fraternity Legacy is likely the best single target dmg dealer in the game, amazing manual overall.
  
  
• Flying Sword - Can be built as a crit fisher or a summoner, both quite strong
  
  
• Bows - Have a good mix of AOE and single target skills, strong attackers overall
  
  
• 1H sword - Despite having just two manuals, the mix of stun/self heal/self buffing make for an excellent baseplate to spice up with the third manual.
  
  
• Polearm - Also only has two manuals, but theyre also both pretty good.
  
  
• Greatword - It sure is a weapon. Not bad, but nothing really notable beyond the cyclone special.
  
  
• Firearm is all over the place, none of the manuals synergize well, but can supplement other builds individually.
  
  
• Sword and Shield - The defensive skills are at best not needed, at worst literal suicide buttons. Helping heart has buffs at least.
  
  
• Scythes - Singular manual is rather mediocre. Bonus crits a are cool, but... Fraternity Legacy.