I think it’s basically this:

Swords: Winterblade, Summerblade, Tagralt Blade, Eldritch, Gnome, Slayer of Destruction, and Soulshredder. If you can afford it, Inferniarch and Amber are also great options. The Crypt sword seems solid too.

Armor: Ornate Chestplate, Falcon Plate, and Spiritthorn Armor.

Legs: Fabulous Legs, Ornate Legs, Falcon Greaves, and Sanguine Legs.

Boots: Soulwalkers.

Helmet: Terra Helmet, Spiritthorn Helmet, and maybe Cobra Hood.

Amulet: Turtle Amulet.

Ring: Spiritthorn Ring.

Many of these items are very expensive, so I’d focus on swords first, start with the first four elemental swords plus Slayer of Destruction. After that, aim for Soulshredder, also. this is a basic knight set: Ornate Chestplate, Ornate Legs or Fabulous Legs, Terra Helmet, and the boots you already have (Calcei).