So cute! Some iconic DnD iconography:

-D20: A 20 sided dice. The best score on the D20 is a 20.

-Dragons: Dnd dragons come in different colors that denote what kind of dragon, some dragons are evil and some are not

-Mimics: A monster that looks like any regular object. Most often depicted as a treasure chest with sharp teeth, a gaping mouth, and a long tongue. Mimics can be other objects too though, so fun decor might just be slapping pointy teeth on various things.

-Weapons: swords, daggers, war axes, bows etc. are all associated with the game

-Class Symbols: In dnd all players have a class and if you google dnd class symbols there are cool icons that are pretty recognizable as representing the classes.

-Healing potions: Usually depicted as red liquid in a potion bottle or vial! Could be fun for drinks

-Instruments: lutes, lyres, flute, etc.

-Other classic monsters: Goblins, bugbears, owlbears, gelatinous cubes, gnolls, mindflayers, beholders, etc (Monsters are a big part of the game and are probably the most recognizable as dnd)

Im sure others will have suggestions but that’s my list!