"Wizards DnD" is common shorthand for the current versions of the pen-and-paper role-playing game Dungeons & Dragons, produced by Wizards of the Coast. Dungeons & Dragons has been published, in one form or another, since 1974.
Originally, Dungeons and Dragons was published by a company that was founded by the two creators of the game specifically to self-publish their work. The company was called Tactical Studies Rules, or TSR. In 1997, TSR was bought out by Wizards of the Coast. Wizards had been publishing Dungeons & Dragons under their own name since the release of the third edition of the game.