Im not necessarily board at all so the title is slightly wrong in that sense.

however, i completed the main quest on my first character with the mages guild questline.

Iv recently been playing a Kajit assassin which is so much fun!

here is what ive done so far :

- Dark brotherhood quests
- bought the home in windhelm
- completed a quest for a dagger...
- done some of the thieves guild
-got 100 sneak
-got 100 alchemy

I love to collect things, i have a room of gems and gold bars. and have various rare items scattered around my home.

any ideas of what i should do next?

First I would finish up the theives guild. It's a good storyline. The daedric and companions are solid as well.

Going to agree with this. There are a good amount of superb quests just around the corner, heck even the quests from the Jarls of the respective holds can be quite good.

Kill everyone you dislike sneakily? maybe?