Abilities that set Terrain
Electric Surge - Sets Electric Terrain
Grassy Surge - Sets Grassy Terrain
Hadron Engine - Sets Electric Terrain
Misty Surge - Sets Misty Terrain
Psychic Surge - Sets Psychic Terrain
Seed Sower - Sets Grassy Terrain
Abilities affected by Terrain
Grass Pelt - Defense raised in Grassy Terrain
Hadron Engine - Special Attack raised in Electric Terrain
Mimicry - Changes type to the Terrain
Quark Drive - Boosts the Pokemon's strongest stat in Electric Terrain
Surge Surfer - Doubles Speed in Electric Terrain
Moves that set Terrain
Electric Terrain - Sets Electric Terrain
Genesis Supernova - Sets Psychic Terrain
Grassy Terrain - Sets Grassy Terrain
Max Lightning - Sets Electric Terrain
Max Mindstorm - Sets Psychic Terrain
Max Overgrowth - Sets Grassy Terrain
Max Starfall - Sets Misty Terrain
Misty Terrain - Sets Misty Terrain
Psychic Terrain - Sets Psychic Terrain
Moves that remove Terrain
Defog
G-Max Wind Rage
Ice Spinner
Splintered Stormshards
Steel Roller
Other moves affected by Terrain
Camouflage - Changes type based on Terrain
Expanding Force - Power increased in Psychic Terrain
Floral Healing - Restores up to 2/3 max HP if used in Grassy Terrain
Grassy Glide - Increased priority in Grassy Terrain
Misty Explosion - Power increased if used in Misty Terrain
Nature Power - Turns into a different move based on Terrain
Rising Voltage - Power increased in Electric Terrain
Secret Power - Chance of different negative effect based on Terrain
Terrain Pulse - Damage increases and type varies if used in a specific Terrain
The items Electric Seed, Grassy Seed, Psychic Seed, and Misty Seed are all consumables for use in Terrain. The former two boost Defense by one stage, while the latter two boost Special Defense by one stage.
To expand on Camouflage, Nature Power, and Secret Power:
Camouflage turns the user's type into Electric in Electric Terrain, Grass in Grassy Terrain, Fairy in Misty Terrain, or Psychic in Psychic Terrain.
Nature Power turns into Thunderbolt in Electric Terrain, Energy Ball in Grassy Terrain, Moonblast in Misty Terrain, or Psychic in Psychic Terrain.
Secret Power has a 30% chance of: paralyzing in Electric Terrain, causing sleep in Grassy Terrain, lowering Special Attack one stage in Misty Terrain, or lowering Speed one stage in Psychic Terrain.
Terrain (Bulbapedia)