This thread is just to reference anything missing that may be useful, not listing in terms of priority or saying the content will be added.
PvM Content:
-Theatre Of Blood
-Xerics bosses: Vespula, guardians
-Xerics puzzles: Ice demon, tightrope, crabs, thieving
-Xerics skilling: Bats
Skilling content:
-Blood & Soul runecrafting altars + dense essence
-Tithe Farm, Spirit tree plots, Special plots
-Motherload, Blast mining
-Ardougne rooftop, wildy course agility
-Falconry hunter
-Blackjacking, pyramid plunder, tzhaar thieving
-Swamp bait fishing
-Construction skill
Missing mechanics/items:
-Should be able to receive runes from trident when uncharging it
-Ardy cloak 1-4
-1 free daily death from zulrah for hcim, either have skills for the diary or pay a fee?
-Update looting bag
-Grand seed pod should teleport home for members
-Fix olm head rotation, and teleports
-Olm mechanics missing: deep burn, fire wall, crystal bombs, life siphon
-Mythical Cape/guild
-Update drop rate for unsired, doesn't show atm
-Add Rune/Addy dragons to slayer tasks
-Clicking under yourself should cancel out retaliate
(Thanks Cape for some more missing content):
-Runecrafting law runes
-Pollniveach rooftops
-Coal bag
-Combining clue scrolls for master clues
-Herbiboar (along with the pet)
-Barbarian assault pet (add to pest control)
-Barbarian fly fishing
-Wintertodt
-All achievement diaries
-Creating or put in shop; Fire, Air, Earth and Water Orbs (you get tons of battlestaffs from pvming but barely any orbs)
-Krystallia(Wildy slayer master) is broken still. If you try to cancel your wilderness task it cancels your normal task.
-Random imps (Dragon, Lucky, Ninjas, Magpies etc) across the worlds
Extra:
-Tons of holiday items that could be used for rewards/minigame/random currency shop
Will be adding more if I find anything, or if anyone would like to add I will put onto the list. Please only osrs related content, not custom suggestions.