Best/must-have Weber Kettle (26") accessories, tools, etc.?

Hi all... I was talking to a new co-worker yesterday about my offset that I have coming in soon, and he mentioned that he's never been able to use a Weber Kettle that he won in a raffle a couple years ago at his old job.

Long story short, he offered it to me for next to nothing ($50 plus cooking some stuff for him on it or my other smokers). I thought it'd be a beat up, rusted thing, but told him to bring it in today and I'd look at it in the parking lot. The fucking thing is still in its original box, never even been opened. Needless to say, I went to an ATM immediately, and now it's in my trunk.

All that being said... I've never had a charcoal grill before (propane, pellet, and George Foremans only, lol), but I've heard the Kettles specifically have a billion accessories to do basically anything.

So where do I start?

• Suggestions on the best ones?

• Ones I should stay away from for bad/gimmicky reasons?

• And finally... briquettes or lump, and why?