A blinded creature can't see and automatically fails any ability check that requires sight. Attack rolls made by blinded creatures have disadvantage. Attacks made against blinded creatures have advantage.
Charmed creatures can't attack the charmer or target the charmer with harmful abilities or magical effects. The charmer has advantage on any ability check to interact socially with the charmed creature.
A dazed or stunned creature is semi-incapacitated and can speak only falteringly. Attacks made against the creature have advantage.
A deafened creature can't hear and automatically fails any ability check that requires hearing.
Fatigued creatures have disadvantage on ability checks and attack rolls, in some cases they can have reduced movement speed as well.
A frightened creature has disadvantage on ability checks and attack rolls while the source of its fear is within line of sight. The creature can't willingly move closer to the source of its fear.
A grappled creature cannot move. The condition ends if the grappler is incapacitated, or if an affect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by a spell.
An incapacitated creature can't move or take any actions on its turn, including free actions. Any attack that hits this creature is a critical hit (does 25 HP of damage) if the attacker is within 5 feet of the incapacitated creature.
An invisible creature is impossible to see without the aid of magic or a special sense. Attacks made against an invisible creature have disadvantage, and the invisible creature's attack rolls have advantage.
A paralyzed creature is incapacitated and can't speak or move. The creature automatically fails all ability checks and attack rolls. Attacks made against a paralyzed creature has advantage.
A petrified creature is transformed, along with any belongings it is wearing or carrying, into a solid inanimate substance (usually stone). The creature also becomes incapacitated. The creature automatically fails all ability checks and attack rolls. The creature becomes immune to poison. Poison already in its system is suspended, not neutralized.
A poisoned creature has disadvantage on attack rolls and ability checks, and can suffer damage over time.
A prone creature's only movement option is to crawl, unless it stands up and thereby ends the condition. The creature has disadvantage on attack rolls. Attacks made against this creature have advantage.
A restrained creature cannot move. Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage. The creature has disadvantage on all ability checks associated with movement (including spell checks).
An unconscious creature is at 0 HP and is incapacitated, can't move or speak, and is unaware of its surroundings. The creature drops whatever it's holding and falls prone.