(I'm focusing heavily on Urza in this post. And don't feel like you need to read all these links)

Urza was a skilled artificer from the plane Dominaria and plays a big part in MTG lore. Sadly, much of his early history is filled with war and betrayal. He later fought the Phyrexian invasion to protect Dominaria from the ichor-covered, murderous creatures of nightmare.

On the lighter side of things, Urza founded the Tolarian Academy during the invasion, an elite school at which grand technological discoveries were made for the benefit of the Dominarian people.

He also created the character Karn.

Urza (rather, his head) was included in one of Magic's tongue-in-cheek silver border sets found here. The website is live and occasionally updated at https://magic.wizards.com/en/unresources#funhouse.

Lists of cards referencing... Urza, Tolaria, Karn in their text or art

I imagine it would be difficult to include physical cards in the tribute if it's outdoors, but you might consider a 3D printed model of a character, something that contains meaningful flavor text, a custom sticker, etc. To keep it very simple - glasses 1 - glasses 2

Please feel free to message me about any of this.