There are some really great mods for Diablo 2. Project Diablo 2 is mod with an active online community that has a season system, plus new abilities and balancing. Its a fantastic mod. Some others exist like Path of Diablo.
Do note that we are currently in a crafting league (a non-standard gameplay mode). If you try the game, you'll need to do it in single player and downgrade to s8[0], or wait until s9 is released.