- Online Yu-gi-oh! Games
- Duel Monsters Genesis
- Kaiba Corp. Virtual Duel System (KCVDS)
- Yu-gi-oh! Online Duel Accelerator
- Yu-gi-oh! Virtual Desktop
- Yu-gi-oh! TCG/OCG Links
- Pojo.biz Boards
- Shriek OCG News
- Official Yu-gi-oh! Website (United States)
- Official Yu-gi-oh! Website (Japan)
- TCGplayer.com Yu-gi-oh! Strategies and Decks
If there's any others that need to be added, or if I miss anything, let me know and I'll add it to the list.
Besides that, I haven't really been focused in on Yu-gi-oh! except for creating cards and waiting on the ban list to be shown by Konami, and I'm waiting on more information on Exceeds Monsters to speculate.