Block Explorers are different avatars that you can used. There are some standard avatars that can be chosen that Upland provides based on your status within the game. Once you reach Director status, you can travel to City Hall in San Francisco to apply for a custom 1 of 1 block explorer. All block explorers (with the exception of the standard ones provided) are assets that you own. Each one has its own description and quantities that exist. Block Explorers can be bought from the Upland store, player run metaventures, or earned by participating in events or challenges.
With the introduction of cars, the different block explorers will be drivers of the cars. If you plan on participating in car racing, it will be important to have a quality driver. Since every block explorer is unique, each explorer will also have different characteristics and driving abilities. Watch the video below to learn a bit more, and also read up about cars in Upland.