Ars Technica has details on the Protecting Children from Abusive Games Act, a bill being put forth by U.S. Senator Josh Hawley (R-Mo.) to regulate loot boxes, microtransactions, and other ways to monetize games targeted at children. They note that this still has a long way to go before being signed into law (here's a refresher on that aspect of this) and also have a reaction from the ESA, who unsurprisingly, are not enthusiastic. The Senator's office has distributed this one-pager to outline how this proposes to regulate games targeting minors or that knowingly allow minors to engage in microtransactions:

In such games, this bill would prohibit several forms of manipulative design:

Loot Boxes

• Microtransactions offering randomized or partially randomized rewards to players

Pay-to-Win

• Manipulation of a game’s progression system – typically by building artificial difficulty or other barriers into game progression – to induce players to spend money on microtransactions to advance through content supposedly available to them at no additional cost
• Pay-to-win - Manipulation of the competitive balance between players of multiplayer games by allowing players who purchase microtransactions competitive advantages over other players

Enforcement

• These rules would be enforced by the Federal Trade Commission, which would treat the distribution of such games by publishers and online distributors as an unfair trade practice.
• State attorneys general would also be empowered to file suit to defend the residents of their states.