E.g., the advanced classes might require more experience points to acquire, or some might not be available until specific objectives have been reached in the game campaign.

GMs may also entirely rule out certain classes, e.g. Acolyte and Mage because their spell-casting abilities do not fit the GM's hard sci-fi scenario.

Instead of using real world currency, such as United States dollar (USD) or Euro (EUR), it’s been replaced with the Wealth bonus.

Player characters typically work for a government agency investigating and/or using this quasi-supernatural force, but this is only a suggestion and is not strictly required by the rules.

Some, however, break that barrier and become aware of the world around them, and help Mages, Acolytes, and other magical characters fight with monsters from another realm.

It uses concepts from the core d20 Modern RPG rules and the Urban Arcana and d20 Menace Manual sourcebooks, which are also recommended for use to get the most from the setting.

The setting allows one to play games that take place during the famous Pulp Era of literature, filled with ancient dinosaurs, power-hungry gangsters, vengeful vigilantes, amazing superheroes, evil Nazis, bizarre inventions, mystical psionics, hard-boiled detectives, trained martial artists, curious explorers, eldritch aliens, and various other fantastic people, places, and things.

Thunderball Rally, released as a preview for the d20 MODERN RPG in Polyhedron #152, is a d20 System mini-game about racing across the United States of America in 1976.

In Thunderball Rally, the player characters portray one of the crews in the largest, most lucrative, most illegal crosscountry road race in America.

[2] Mark Theuar, for the gaming magazine Fictional Reality, wrote that he would "highly recommend this book to anyone wanting to play in a modern day rpg" and that "the interior artwork has sort of a graphic novel feel to it and it works very well for this setting".

[3] He highlighted his enjoyment of the section on guns and that "combat is similar to Call of Cthulhu d20 meaning that you can get dead real quick.

[3] Academic Kris Green also highlighted the d20 Modern Wealth system in the book Mathematics in Popular Culture (2012) and called it an "excellent example of abstraction".

[4] Charlie Hall, for Polygon, stated that "back in 2002, d20 Modern helped to breathe life into third edition Dungeons & Dragons, expanding the tabletop role-playing game into a far more contemporary setting — less swords and sorcery, more ninjas and automatic weapons".

[6] This new wave included hundreds of third-party publications alongside the additional ten d20 Modern books Wizards of the Coast released.

Appelcline wrote that "Sword & Sorcery was probably the most noticeable, with their licensed version of Gamma World (2003-2004), though they covered their bets by saying the books could be used with D&D 3e or d20 Modern.

Some of the most notable were Adamant's Thrilling Tales (2005-2007) and Mars (2006-2007) line, Green Ronin's varied d20 Modern rules and settings, which culminated in Damnation Decade (2006), and Mongoose's new editions of the classic Macho Women with Guns (2003, 2005)".

[6] In 2022, Jeff Grubb – co-creator of d20 Modern – announced an upcoming role-playing system titled Everyday Heroes which is based on the 5th edition Dungeons & Dragons ruleset via Wizard's Open Game License.

Sigfried Trent, one of the lead designers, described the game as merger of "the theme, the setting, the mood, the feeling of d20 Modern" and "the rules, the simplicity, and the modularity of 5e".

[5] This system will be published by Evil Genius Games and will include licensed settings such as Escape from New York, Highlander, Kong: Skull Island, Pacific Rim, Rambo, The Crow, Total Recall, and Universal Soldier.