In such a case, if a DM really wanted to, they could quickly point to the table on page 45 of the PHB which says a Druid's Armor and Weapon Proficiencies are:
Light and medium armor (nonmetal), shields (nonmetal), clubs, daggers, darts, javelins, maces, quarterstaffs, scimitars, sickles, slings, spears
And the game would proceed from there with the DM describing the scene, the player deciding what their character would like to do next, and the DM adjudicating accordingly. No improvisation or homebrew necessary, at least in some circles.