Normal Dungeons, LFG or guild, 340
Heroic Dungeons, LFG or guild, 355
Mythic + dungeons, guild or custom groups, 370-400
Weekly Mythic+ cache, up to 410 after a couple of weeks.
Weekly dungeon quest : (I had no idea this existed): 370
Timewalking: 320, also a weekly quest for a 370
Darkshore world boss: 400
Darkshore main quest: 400
Darkshore base warfront reward: 355
Arathi world boss: 370
Arathi main quest: 370
Arathi base warfront reward: 340
Crafted armour: auctionhouse, self crafted: 340
Crafted weapons, rings 300-310
Darkmoon trinkets: 355
Elite crafted: bop self-crafted: 415
BoE world drops
Emissary: up to 385. Can reward 2000 gold.
Items from world quests: ?
World boss: pug, 355
Faction assault: ? (currently 370)
Faction assault token vendor sells a 395 ring
weekly quest: 2500 AP and treasure map for 4 heroic or 3 mythic runs.
Each run can drop doubloons, pets, mounts or ilvl 325 weapons.
Rep, gold, battle-scarred runes, in return for AP. (runes should be done on every 120 alt)
Followers can be equipped to give bonus resources.
free 45 ilvls on the amulet from Magni in Silithus for alts if your main is revered.
Vendors sell 320 cloak at Revered and 350-355 items at Exalted.
Contracts made by scribe give +10 per world quest to a single BFA faction.
Paragon bags reward 3500-5000 gold, AP, WR and some pets, toys or recipes varying by each faction.
Rated pvp rewards are based on your pvp rank, rank 2400+ for the best rewards.
End of match rewards: occasional 370-405
Weekly cache rewards 385-415
Weekly chest rewards 385-415
World pvp quests (Alliance get a quest to kill 25 horde players awarding a 370 item)
Titan Residuum vendor:
vendor: up to 415 best in slot
Seals of Wartorn Fate
reroll a loot drop
Note: all pet content is valid forever unlike ilvl bound equipment.
Dailies. Daily pet quests include BFA world quests, Legion world quests, garrison daily pet quests, wild pet trainer dailies, Celestial Tournament, Argent tournament.
Weekly dungeons: Wailing Caverns, Gnomeregan (Deadmines isn't worth repeating because the pets can't be caged).
Old world farming
Old content raids had pets added to their loot tables (generally 3 pets available per raid) and can drop mounts etc. These are on weekly timers.
Open world mounts pets and transmog can be farmed at any time (but my recent testing revealed it's kinda boring to kill 100s of world mobs for a 1 in 1000 chance of a pet).
Any additions or corrections are welcome, not all ilvls are fully implemented right away ( I haven't attempted to address the very complicated rollouts).