Some are team events...
Also you can get, either build or buy in game using in game coins, higher weapons and such.. some potions do increase your levels.
I prefer to make my own stuff... I do have the Highest in Game Non-Member armor available... I bought that... took me 2 months of selling highest makeable cooking items at the time, Chocolate Cakes ( level 50 )... I can make up to level 90 now. That was about 6 or so years ago... I've been playing since '04! ( Wasn't a member then... was more like mid-30's in free worlder stuff... they had just upgraded everything to 99 levels maxed ).
I also make armor, weapons and just sold runes, potions and various items... IF I sold everything sellable in my bank, about almost 1 and a half Billion... or so... I currently have 55 Million and change in coins...
The game isn't just about beating up things... it's to unwind.. I've been a member for like 6 years... I play at most, about 3 hours a day give or take, mostly on the weekends... it adds up.
Black Queen Dragon is
only 900 levels, try fighting the Kalphite King, level
2500! But there is a Keris dagger that helps.
Full listing of creatures:
https://www.tip.it/runescape/bestiaryhttps://www.tip.it/runescape/items/view/6655-kerisI believe you can apply poison to the blade as an attachment, which might help...
Haven't tried it, but I have seen both Dragon off-hand and Dragon Daggers with Weapon Poison... but a little research says as of 2012 it was removed from the game... might have to double check it, I have a friend who has one, or rather had one... still plays on and off. I'll ask them...
TT